Wow I noticed something!
To prevent ram overflow with gpu training allocations, I'm using a 2TB
Samsung 870 evo for swap.
As you can see below, swap usage 18Gi and server was idle, that means maybe
ceph client hits latency because of the swap usage.
root@bmw-m4:/sys/kernel/debug/ceph/e42fd4b0-313b-11ee-9a00-31da71873773.client1275577#
free -h
total used free shared buff/cache
available
Mem: 62Gi 34Gi 27Gi 0.0Ki 639Mi
27Gi
Swap: 1.8Ti 18Gi 1.8Ti
I decided to play around kernel parameters to prevent ceph swap usage.
kernel.shmmax = 60654764851 # Maximum shared segment size in bytes
> kernel.shmall = 16453658 # Maximum number of shared memory segments in
> pages
> vm.nr_hugepages = 4096 # Increase Transparent Huge Pages (THP) Defrag:
> vm.swappiness = 0 # Set vm.swappiness to 0 to minimize swapping
> vm.min_free_kbytes = 1048576 # required free memory (set to 1% of physical
> ram)
I reboot the server and after reboot swap usage is 0 as expected.
To give a try I started the iobench.sh (
https://github.com/ozkangoksu/benchmark/blob/main/iobench.sh)
This client has 1G nic only. As you can see below, other then 4K block
size, ceph client can saturate NIC.
root@bmw-m4:~# nicstat -MUz 1
Time Int rMbps wMbps rPk/s wPk/s rAvs wAvs %rUtil
%wUtil
01:04:48 ens1f0 936.9 92.90 91196.8 60126.3 1346.6 202.5 98.2
9.74
root@bmw-m4:/mounts/ud-data/benchuser1/96f13211-c37f-42db-8d05-f3255a05129e/testdir#
bash iobench.sh
Seq Write benchmarking: size=1G,direct=1,numjobs=3,iodepth=32
BS=1M write: IOPS=112, BW=112MiB/s (118MB/s)(3072MiB/27395msec); 0 zone
resets
BS=128K write: IOPS=894, BW=112MiB/s (117MB/s)(3072MiB/27462msec); 0 zone
resets
BS=64K write: IOPS=1758, BW=110MiB/s (115MB/s)(3072MiB/27948msec); 0
zone resets
BS=32K write: IOPS=3542, BW=111MiB/s (116MB/s)(3072MiB/27748msec); 0
zone resets
BS=16K write: IOPS=6839, BW=107MiB/s (112MB/s)(3072MiB/28747msec); 0
zone resets
BS=4K write: IOPS=8473, BW=33.1MiB/s (34.7MB/s)(3072MiB/92813msec); 0
zone resets
Seq Read benchmarking: size=1G,direct=1,numjobs=3,iodepth=32
BS=1M read: IOPS=112, BW=112MiB/s (118MB/s)(3072MiB/27386msec)
BS=128K read: IOPS=895, BW=112MiB/s (117MB/s)(3072MiB/27431msec)
BS=64K read: IOPS=1788, BW=112MiB/s (117MB/s)(3072MiB/27486msec)
BS=32K read: IOPS=3561, BW=111MiB/s (117MB/s)(3072MiB/27603msec)
BS=16K read: IOPS=6924, BW=108MiB/s (113MB/s)(3072MiB/28392msec)
BS=4K read: IOPS=21.3k, BW=83.3MiB/s (87.3MB/s)(3072MiB/36894msec)
Rand Write benchmarking: size=1G,direct=1,numjobs=3,iodepth=32
BS=1M write: IOPS=112, BW=112MiB/s (118MB/s)(3072MiB/27406msec); 0 zone
resets
BS=128K write: IOPS=894, BW=112MiB/s (117MB/s)(3072MiB/27466msec); 0 zone
resets
BS=64K write: IOPS=1781, BW=111MiB/s (117MB/s)(3072MiB/27591msec); 0
zone resets
BS=32K write: IOPS=3545, BW=111MiB/s (116MB/s)(3072MiB/27729msec); 0
zone resets
BS=16K write: IOPS=6823, BW=107MiB/s (112MB/s)(3072MiB/28814msec); 0
zone resets
BS=4K write: IOPS=12.7k, BW=49.8MiB/s (52.2MB/s)(3072MiB/61694msec); 0
zone resets
Rand Read benchmarking: size=1G,direct=1,numjobs=3,iodepth=32
BS=1M read: IOPS=112, BW=112MiB/s (118MB/s)(3072MiB/27388msec)
BS=128K read: IOPS=894, BW=112MiB/s (117MB/s)(3072MiB/27479msec)
BS=64K read: IOPS=1784, BW=112MiB/s (117MB/s)(3072MiB/27547msec)
BS=32K read: IOPS=3559, BW=111MiB/s (117MB/s)(3072MiB/27614msec)
BS=16K read: IOPS=7047, BW=110MiB/s (115MB/s)(3072MiB/27897msec)
BS=4K read: IOPS=26.9k, BW=105MiB/s (110MB/s)(3072MiB/29199msec)
root@bmw-m4:/sys/kernel/debug/ceph/e42fd4b0-313b-11ee-9a00-31da71873773.client1818702#
cat metrics
item total
------------------------------------------
opened files / total inodes 0 / 109
pinned i_caps / total inodes 109 / 109
opened inodes / total inodes 0 / 109
item total avg_lat(us) min_lat(us) max_lat(us)
stdev(us)
-----------------------------------------------------------------------------------
read 2316289 13904 221 8827984
760
write 2317824 21152 2975 9243821
2365
metadata 170 5944 225 202505
24314
item total avg_sz(bytes) min_sz(bytes) max_sz(bytes)
total_sz(bytes)
----------------------------------------------------------------------------------------
read 2316289 16688 4096 1048576
38654712361
write 2317824 19457 4096 4194304
45097156608
item total miss hit
-------------------------------------------------
d_lease 112 3 858
caps 109 58 6963547
root@bmw-m4:/sys/kernel/debug/ceph/e42fd4b0-313b-11ee-9a00-31da71873773.client1818702#
free -h
total used free shared buff/cache
available
Mem: 62Gi 11Gi 50Gi 3.0Mi 1.0Gi
49Gi
Swap: 1.8Ti 0B 1.8Ti
I started to feel we are getting closer :)
Özkan Göksu <ozkangksu@xxxxxxxxx>, 27 Oca 2024 Cmt, 02:58 tarihinde şunu
yazdı:
> I started to investigate my clients.
>
> for example:
>
> root@ud-01:~# ceph health detail
> HEALTH_WARN 1 clients failing to respond to cache pressure
> [WRN] MDS_CLIENT_RECALL: 1 clients failing to respond to cache pressure
> mds.ud-data.ud-02.xcoojt(mds.0): Client bmw-m4 failing to respond to
> cache pressure client_id: 1275577
>
> root@ud-01:~# ceph fs status
> ud-data - 86 clients
> =======
> RANK STATE MDS ACTIVITY DNS INOS DIRS
> CAPS
> 0 active ud-data.ud-02.xcoojt Reqs: 34 /s 2926k 2827k 155k
> 1157k
>
>
> ceph tell mds.ud-data.ud-02.xcoojt session ls | jq -r '.[] | "clientid:
> \(.id)= num_caps: \(.num_caps), num_leases: \(.num_leases),
> request_load_avg: \(.request_load_avg), num_completed_requests:
> \(.num_completed_requests), num_completed_flushes:
> \(.num_completed_flushes)"' | sort -n -t: -k3
>
> clientid: *1275577*= num_caps: 12312, num_leases: 0, request_load_avg: 0,
> num_completed_requests: 0, num_completed_flushes: 1
> clientid: 1275571= num_caps: 16307, num_leases: 1, request_load_avg: 2101,
> num_completed_requests: 0, num_completed_flushes: 3
> clientid: 1282130= num_caps: 26337, num_leases: 3, request_load_avg: 116,
> num_completed_requests: 0, num_completed_flushes: 1
> clientid: 1191789= num_caps: 32784, num_leases: 0, request_load_avg: 1846,
> num_completed_requests: 0, num_completed_flushes: 0
> clientid: 1275535= num_caps: 79825, num_leases: 2, request_load_avg: 133,
> num_completed_requests: 8, num_completed_flushes: 8
> clientid: 1282142= num_caps: 80581, num_leases: 6, request_load_avg: 125,
> num_completed_requests: 2, num_completed_flushes: 6
> clientid: 1275532= num_caps: 87836, num_leases: 3, request_load_avg: 190,
> num_completed_requests: 2, num_completed_flushes: 6
> clientid: 1275547= num_caps: 94129, num_leases: 4, request_load_avg: 149,
> num_completed_requests: 2, num_completed_flushes: 4
> clientid: 1275553= num_caps: 96460, num_leases: 4, request_load_avg: 155,
> num_completed_requests: 2, num_completed_flushes: 8
> clientid: 1282139= num_caps: 108882, num_leases: 25, request_load_avg: 99,
> num_completed_requests: 2, num_completed_flushes: 4
> clientid: 1275538= num_caps: 437162, num_leases: 0, request_load_avg: 101,
> num_completed_requests: 2, num_completed_flushes: 0
>
> --------------------------------------
>
> *MY CLIENT:*
>
> The client is actually at idle mode and there is no reason to fail at all.
>
> root@bmw-m4:~# apt list --installed |grep ceph
> ceph-common/jammy-updates,now 17.2.6-0ubuntu0.22.04.2 amd64 [installed]
> libcephfs2/jammy-updates,now 17.2.6-0ubuntu0.22.04.2 amd64
> [installed,automatic]
> python3-ceph-argparse/jammy-updates,now 17.2.6-0ubuntu0.22.04.2 amd64
> [installed,automatic]
> python3-ceph-common/jammy-updates,now 17.2.6-0ubuntu0.22.04.2 all
> [installed,automatic]
> python3-cephfs/jammy-updates,now 17.2.6-0ubuntu0.22.04.2 amd64
> [installed,automatic]
>
> Let's check metrics and stats:
>
> root@bmw-m4:/sys/kernel/debug/ceph/e42fd4b0-313b-11ee-9a00-31da71873773.client1275577#
> cat metrics
> item total
> ------------------------------------------
> opened files / total inodes 2 / 12312
> pinned i_caps / total inodes 12312 / 12312
> opened inodes / total inodes 1 / 12312
>
> item total avg_lat(us) min_lat(us) max_lat(us)
> stdev(us)
>
> -----------------------------------------------------------------------------------
> read 22283 44409 430 1804853
> 15619
> write 112702 419725 3658 8879541
> 6008
> metadata 353322 5712 154 917903
> 5357
>
> item total avg_sz(bytes) min_sz(bytes) max_sz(bytes)
> total_sz(bytes)
>
> ----------------------------------------------------------------------------------------
> read 22283 1701940 1 4194304
> 37924318602
> write 112702 246211 1 4194304
> 27748469309
>
> item total miss hit
> -------------------------------------------------
> d_lease 62 63627 28564698
> caps 12312 36658 44568261
>
>
> root@bmw-m4:/sys/kernel/debug/ceph/e42fd4b0-313b-11ee-9a00-31da71873773.client1275577#
> cat bdi/stats
> BdiWriteback: 0 kB
> BdiReclaimable: 800 kB
> BdiDirtyThresh: 0 kB
> DirtyThresh: 5795340 kB
> BackgroundThresh: 2894132 kB
> BdiDirtied: 27316320 kB
> BdiWritten: 27316320 kB
> BdiWriteBandwidth: 1472 kBps
> b_dirty: 0
> b_io: 0
> b_more_io: 0
> b_dirty_time: 0
> bdi_list: 1
> state: 1
>
>
> Last 3 days dmesg output:
>
> [Wed Jan 24 16:45:13 2024] xfsettingsd[653036]: segfault at 18 ip
> 00007fbd12f5d337 sp 00007ffd254332a0 error 4 in
> libxklavier.so.16.4.0[7fbd12f4d000+19000]
> [Wed Jan 24 16:45:13 2024] Code: 4c 89 e7 e8 0b 56 ff ff 48 89 03 48 8b 5c
> 24 30 e9 d1 fd ff ff e8 b9 5b ff ff 66 0f 1f 84 00 00 00 00 00 41 54 55 48
> 89 f5 53 <48> 8b 42 18 48 89 d1 49 89 fc 48 89 d3 48 89 fa 48 89 ef 48 8b b0
> [Thu Jan 25 06:51:31 2024] NVRM: GPU at PCI:0000:81:00:
> GPU-02efbb18-c9e4-3a16-d615-598959520b99
> [Thu Jan 25 06:51:31 2024] NVRM: GPU Board Serial Number: 1321421015411
> [Thu Jan 25 06:51:31 2024] NVRM: Xid (PCI:0000:81:00): 43, pid=683281,
> name=python, Ch 00000008
> [Thu Jan 25 06:56:49 2024] NVRM: Xid (PCI:0000:81:00): 43, pid=683377,
> name=python, Ch 00000018
> [Thu Jan 25 20:14:13 2024] NVRM: Xid (PCI:0000:81:00): 43, pid=696062,
> name=python, Ch 00000008
> [Fri Jan 26 04:05:40 2024] NVRM: Xid (PCI:0000:81:00): 43, pid=700166,
> name=python, Ch 00000008
> [Fri Jan 26 05:05:12 2024] NVRM: Xid (PCI:0000:81:00): 43, pid=700320,
> name=python, Ch 00000008
> [Fri Jan 26 05:44:50 2024] NVRM: GPU at PCI:0000:82:00:
> GPU-3af62a2c-e7eb-a7d5-c073-22f06dc7065f
> [Fri Jan 26 05:44:50 2024] NVRM: GPU Board Serial Number: 1321421010400
> [Fri Jan 26 05:44:50 2024] NVRM: Xid (PCI:0000:82:00): 43, pid=700757,
> name=python, Ch 00000018
> [Fri Jan 26 05:56:02 2024] NVRM: Xid (PCI:0000:81:00): 43, pid=701096,
> name=python, Ch 00000028
> [Fri Jan 26 06:34:20 2024] NVRM: Xid (PCI:0000:81:00): 43, pid=701226,
> name=python, Ch 00000038
>
> root@bmw-m4:/sys/kernel/debug/ceph/e42fd4b0-313b-11ee-9a00-31da71873773.client1275577#
> free -h
> total used free shared buff/cache
> available
> Mem: 62Gi 34Gi 27Gi 0.0Ki 639Mi
> 27Gi
> Swap: 1.8Ti 18Gi 1.8Ti
>
> root@bmw-m4:/sys/kernel/debug/ceph/e42fd4b0-313b-11ee-9a00-31da71873773.client1275577#
> cat /proc/vmstat
> nr_free_pages 7231171
> nr_zone_inactive_anon 7924766
> nr_zone_active_anon 525190
> nr_zone_inactive_file 44029
> nr_zone_active_file 55966
> nr_zone_unevictable 13042
> nr_zone_write_pending 3
> nr_mlock 13042
> nr_bounce 0
> nr_zspages 0
> nr_free_cma 0
> numa_hit 6701928919
> numa_miss 312628341
> numa_foreign 312628341
> numa_interleave 31538
> numa_local 6701864751
> numa_other 312692567
> nr_inactive_anon 7924766
> nr_active_anon 525190
> nr_inactive_file 44029
> nr_active_file 55966
> nr_unevictable 13042
> nr_slab_reclaimable 61076
> nr_slab_unreclaimable 63509
> nr_isolated_anon 0
> nr_isolated_file 0
> workingset_nodes 3934
> workingset_refault_anon 30325493
> workingset_refault_file 14593094
> workingset_activate_anon 5376050
> workingset_activate_file 3250679
> workingset_restore_anon 292317
> workingset_restore_file 1166673
> workingset_nodereclaim 488665
> nr_anon_pages 8451968
> nr_mapped 35731
> nr_file_pages 138824
> nr_dirty 3
> nr_writeback 0
> nr_writeback_temp 0
> nr_shmem 242
> nr_shmem_hugepages 0
> nr_shmem_pmdmapped 0
> nr_file_hugepages 0
> nr_file_pmdmapped 0
> nr_anon_transparent_hugepages 3588
> nr_vmscan_write 33746573
> nr_vmscan_immediate_reclaim 160
> nr_dirtied 48165341
> nr_written 80207893
> nr_kernel_misc_reclaimable 0
> nr_foll_pin_acquired 174002
> nr_foll_pin_released 174002
> nr_kernel_stack 60032
> nr_page_table_pages 46041
> nr_swapcached 36166
> nr_dirty_threshold 1448010
> nr_dirty_background_threshold 723121
> pgpgin 129904699
> pgpgout 299261581
> pswpin 30325493
> pswpout 45158221
> pgalloc_dma 1024
> pgalloc_dma32 57788566
> pgalloc_normal 6956384725
> pgalloc_movable 0
> allocstall_dma 0
> allocstall_dma32 0
> allocstall_normal 188
> allocstall_movable 63024
> pgskip_dma 0
> pgskip_dma32 0
> pgskip_normal 0
> pgskip_movable 0
> pgfree 7222273815
> pgactivate 1371753960
> pgdeactivate 18329381
> pglazyfree 10
> pgfault 7795723861
> pgmajfault 4600007
> pglazyfreed 0
> pgrefill 18575528
> pgreuse 81910383
> pgsteal_kswapd 980532060
> pgsteal_direct 38942066
> pgdemote_kswapd 0
> pgdemote_direct 0
> pgscan_kswapd 1135293298
> pgscan_direct 58883653
> pgscan_direct_throttle 15
> pgscan_anon 220939938
> pgscan_file 973237013
> pgsteal_anon 46538607
> pgsteal_file 972935519
> zone_reclaim_failed 0
> pginodesteal 0
> slabs_scanned 25879882
> kswapd_inodesteal 2179831
> kswapd_low_wmark_hit_quickly 152797
> kswapd_high_wmark_hit_quickly 32025
> pageoutrun 204447
> pgrotated 44963935
> drop_pagecache 0
> drop_slab 0
> oom_kill 0
> numa_pte_updates 2724410955
> numa_huge_pte_updates 1695890
> numa_hint_faults 1739823254
> numa_hint_faults_local 1222358972
> numa_pages_migrated 312611639
> pgmigrate_success 510846802
> pgmigrate_fail 875493
> thp_migration_success 156413
> thp_migration_fail 2
> thp_migration_split 0
> compact_migrate_scanned 1274073243
> compact_free_scanned 8430842597
> compact_isolated 400278352
> compact_stall 145300
> compact_fail 128562
> compact_success 16738
> compact_daemon_wake 170247
> compact_daemon_migrate_scanned 35486283
> compact_daemon_free_scanned 369870412
> htlb_buddy_alloc_success 0
> htlb_buddy_alloc_fail 0
> unevictable_pgs_culled 2774290
> unevictable_pgs_scanned 0
> unevictable_pgs_rescued 2675031
> unevictable_pgs_mlocked 2813622
> unevictable_pgs_munlocked 2674972
> unevictable_pgs_cleared 84231
> unevictable_pgs_stranded 84225
> thp_fault_alloc 416468
> thp_fault_fallback 19181
> thp_fault_fallback_charge 0
> thp_collapse_alloc 17931
> thp_collapse_alloc_failed 76
> thp_file_alloc 0
> thp_file_fallback 0
> thp_file_fallback_charge 0
> thp_file_mapped 0
> thp_split_page 2
> thp_split_page_failed 0
> thp_deferred_split_page 66
> thp_split_pmd 22451
> thp_split_pud 0
> thp_zero_page_alloc 1
> thp_zero_page_alloc_failed 0
> thp_swpout 22332
> thp_swpout_fallback 0
> balloon_inflate 0
> balloon_deflate 0
> balloon_migrate 0
> swap_ra 25777929
> swap_ra_hit 25658825
> direct_map_level2_splits 1249
> direct_map_level3_splits 49
> nr_unstable 0
>
>
>
> Özkan Göksu <ozkangksu@xxxxxxxxx>, 27 Oca 2024 Cmt, 02:36 tarihinde şunu
> yazdı:
>
>> Hello Frank.
>>
>> I have 84 clients (high-end servers) with: Ubuntu 20.04.5 LTS - Kernel:
>> Linux 5.4.0-125-generic
>>
>> My cluster 17.2.6 quincy.
>> I have some client nodes with "ceph-common/stable,now 17.2.7-1focal" I
>> wonder using new version clients is the main problem?
>> Maybe I have a communication error. For example I hit this problem and I
>> can not collect client stats "
>> https://github.com/ceph/ceph/pull/52127/files";
>>
>> Best regards.
>>
>>
>>
>> Frank Schilder <frans@xxxxxx>, 26 Oca 2024 Cum, 14:53 tarihinde şunu
>> yazdı:
>>
>>> Hi, this message is one of those that are often spurious. I don't recall
>>> in which thread/PR/tracker I read it, but the story was something like that:
>>>
>>> If an MDS gets under memory pressure it will request dentry items back
>>> from *all* clients, not just the active ones or the ones holding many of
>>> them. If you have a client that's below the min-threshold for dentries (its
>>> one of the client/mds tuning options), it will not respond. This client
>>> will be flagged as not responding, which is a false positive.
>>>
>>> I believe the devs are working on a fix to get rid of these spurious
>>> warnings. There is a "bug/feature" in the MDS that does not clear this
>>> warning flag for inactive clients. Hence, the message hangs and never
>>> disappears. I usually clear it with a "echo 3 > /proc/sys/vm/drop_caches"
>>> on the client. However, except for being annoying in the dashboard, it has
>>> no performance or otherwise negative impact.
>>>
>>> Best regards,
>>> =================
>>> Frank Schilder
>>> AIT Risø Campus
>>> Bygning 109, rum S14
>>>
>>> ________________________________________
>>> From: Eugen Block <eblock@xxxxxx>
>>> Sent: Friday, January 26, 2024 10:05 AM
>>> To: Özkan Göksu
>>> Cc: ceph-users@xxxxxxx
>>> Subject: Re: 1 clients failing to respond to cache pressure
>>> (quincy:17.2.6)
>>>
>>> Performance for small files is more about IOPS rather than throughput,
>>> and the IOPS in your fio tests look okay to me. What you could try is
>>> to split the PGs to get around 150 or 200 PGs per OSD. You're
>>> currently at around 60 according to the ceph osd df output. Before you
>>> do that, can you share 'ceph pg ls-by-pool cephfs.ud-data.data |
>>> head'? I don't need the whole output, just to see how many objects
>>> each PG has. We had a case once where that helped, but it was an older
>>> cluster and the pool was backed by HDDs and separate rocksDB on SSDs.
>>> So this might not be the solution here, but it could improve things as
>>> well.
>>>
>>>
>>> Zitat von Özkan Göksu <ozkangksu@xxxxxxxxx>:
>>>
>>> > Every user has a 1x subvolume and I only have 1 pool.
>>> > At the beginning we were using each subvolume for ldap home directory +
>>> > user data.
>>> > When a user logins any docker on any host, it was using the cluster for
>>> > home and the for user related data, we was have second directory in the
>>> > same subvolume.
>>> > Time to time users were feeling a very slow home environment and after
>>> a
>>> > month it became almost impossible to use home. VNC sessions became
>>> > unresponsive and slow etc.
>>> >
>>> > 2 weeks ago, I had to migrate home to a ZFS storage and now the overall
>>> > performance is better for only user_data without home.
>>> > But still the performance is not good enough as I expected because of
>>> the
>>> > problems related to MDS.
>>> > The usage is low but allocation is high and Cpu usage is high. You saw
>>> the
>>> > IO Op/s, it's nothing but allocation is high.
>>> >
>>> > I develop a fio benchmark script and I run the script on 4x test
>>> server at
>>> > the same time, the results are below:
>>> > Script:
>>> >
>>> https://github.com/ozkangoksu/benchmark/blob/8f5df87997864c25ef32447e02fcd41fda0d2a67/iobench.sh
>>> >
>>> >
>>> https://github.com/ozkangoksu/benchmark/blob/main/benchmark-results/iobench-client-01.txt
>>> >
>>> https://github.com/ozkangoksu/benchmark/blob/main/benchmark-results/iobench-client-02.txt
>>> >
>>> https://github.com/ozkangoksu/benchmark/blob/main/benchmark-results/iobench-client-03.txt
>>> >
>>> https://github.com/ozkangoksu/benchmark/blob/main/benchmark-results/iobench-client-04.txt
>>> >
>>> > While running benchmark, I take sample values for each type of iobench
>>> run.
>>> >
>>> > Seq Write benchmarking: size=1G,direct=1,numjobs=3,iodepth=32
>>> > client: 70 MiB/s rd, 762 MiB/s wr, 337 op/s rd, 24.41k op/s wr
>>> > client: 60 MiB/s rd, 551 MiB/s wr, 303 op/s rd, 35.12k op/s wr
>>> > client: 13 MiB/s rd, 161 MiB/s wr, 101 op/s rd, 41.30k op/s wr
>>> >
>>> > Seq Read benchmarking: size=1G,direct=1,numjobs=3,iodepth=32
>>> > client: 1.6 GiB/s rd, 219 KiB/s wr, 28.76k op/s rd, 89 op/s wr
>>> > client: 370 MiB/s rd, 475 KiB/s wr, 90.38k op/s rd, 89 op/s wr
>>> >
>>> > Rand Write benchmarking: size=1G,direct=1,numjobs=3,iodepth=32
>>> > client: 63 MiB/s rd, 1.5 GiB/s wr, 8.77k op/s rd, 5.50k op/s wr
>>> > client: 14 MiB/s rd, 1.8 GiB/s wr, 81 op/s rd, 13.86k op/s wr
>>> > client: 6.6 MiB/s rd, 1.2 GiB/s wr, 61 op/s rd, 30.13k op/s wr
>>> >
>>> > Rand Read benchmarking: size=1G,direct=1,numjobs=3,iodepth=32
>>> > client: 317 MiB/s rd, 841 MiB/s wr, 426 op/s rd, 10.98k op/s wr
>>> > client: 2.8 GiB/s rd, 882 MiB/s wr, 25.68k op/s rd, 291 op/s wr
>>> > client: 4.0 GiB/s rd, 226 MiB/s wr, 89.63k op/s rd, 124 op/s wr
>>> > client: 2.4 GiB/s rd, 295 KiB/s wr, 197.86k op/s rd, 20 op/s wr
>>> >
>>> > It seems I only have problems with the 4K,8K,16K other sector sizes.
>>> >
>>> >
>>> >
>>> >
>>> > Eugen Block <eblock@xxxxxx>, 25 Oca 2024 Per, 19:06 tarihinde şunu
>>> yazdı:
>>> >
>>> >> I understand that your MDS shows a high CPU usage, but other than that
>>> >> what is your performance issue? Do users complain? Do some operations
>>> >> take longer than expected? Are OSDs saturated during those phases?
>>> >> Because the cache pressure messages don’t necessarily mean that users
>>> >> will notice.
>>> >> MDS daemons are single-threaded so that might be a bottleneck. In that
>>> >> case multi-active mds might help, which you already tried and
>>> >> experienced OOM killers. But you might have to disable the mds
>>> >> balancer as someone else mentioned. And then you could think about
>>> >> pinning, is it possible to split the CephFS into multiple
>>> >> subdirectories and pin them to different ranks?
>>> >> But first I’d still like to know what the performance issue really is.
>>> >>
>>> >> Zitat von Özkan Göksu <ozkangksu@xxxxxxxxx>:
>>> >>
>>> >> > I will try my best to explain my situation.
>>> >> >
>>> >> > I don't have a separate mds server. I have 5 identical nodes, 3 of
>>> them
>>> >> > mons, and I use the other 2 as active and standby mds. (currently I
>>> have
>>> >> > left overs from max_mds 4)
>>> >> >
>>> >> > root@ud-01:~# ceph -s
>>> >> > cluster:
>>> >> > id: e42fd4b0-313b-11ee-9a00-31da71873773
>>> >> > health: HEALTH_WARN
>>> >> > 1 clients failing to respond to cache pressure
>>> >> >
>>> >> > services:
>>> >> > mon: 3 daemons, quorum ud-01,ud-02,ud-03 (age 9d)
>>> >> > mgr: ud-01.qycnol(active, since 8d), standbys: ud-02.tfhqfd
>>> >> > mds: 1/1 daemons up, 4 standby
>>> >> > osd: 80 osds: 80 up (since 9d), 80 in (since 5M)
>>> >> >
>>> >> > data:
>>> >> > volumes: 1/1 healthy
>>> >> > pools: 3 pools, 2305 pgs
>>> >> > objects: 106.58M objects, 25 TiB
>>> >> > usage: 45 TiB used, 101 TiB / 146 TiB avail
>>> >> > pgs: 2303 active+clean
>>> >> > 2 active+clean+scrubbing+deep
>>> >> >
>>> >> > io:
>>> >> > client: 16 MiB/s rd, 3.4 MiB/s wr, 77 op/s rd, 23 op/s wr
>>> >> >
>>> >> > ------------------------------
>>> >> > root@ud-01:~# ceph fs status
>>> >> > ud-data - 84 clients
>>> >> > =======
>>> >> > RANK STATE MDS ACTIVITY DNS INOS
>>> DIRS
>>> >> > CAPS
>>> >> > 0 active ud-data.ud-02.xcoojt Reqs: 40 /s 2579k 2578k
>>> 169k
>>> >> > 3048k
>>> >> > POOL TYPE USED AVAIL
>>> >> > cephfs.ud-data.meta metadata 136G 44.9T
>>> >> > cephfs.ud-data.data data 44.3T 44.9T
>>> >> >
>>> >> > ------------------------------
>>> >> > root@ud-01:~# ceph health detail
>>> >> > HEALTH_WARN 1 clients failing to respond to cache pressure
>>> >> > [WRN] MDS_CLIENT_RECALL: 1 clients failing to respond to cache
>>> pressure
>>> >> > mds.ud-data.ud-02.xcoojt(mds.0): Client bmw-m4 failing to
>>> respond to
>>> >> > cache pressure client_id: 1275577
>>> >> >
>>> >> > ------------------------------
>>> >> > When I check the failing client with session ls I see only
>>> "num_caps:
>>> >> 12298"
>>> >> >
>>> >> > ceph tell mds.ud-data.ud-02.xcoojt session ls | jq -r '.[] |
>>> "clientid:
>>> >> > \(.id)= num_caps: \(.num_caps), num_leases: \(.num_leases),
>>> >> > request_load_avg: \(.request_load_avg), num_completed_requests:
>>> >> > \(.num_completed_requests), num_completed_flushes:
>>> >> > \(.num_completed_flushes)"' | sort -n -t: -k3
>>> >> >
>>> >> > clientid: 1275577= num_caps: 12298, num_leases: 0,
>>> request_load_avg: 0,
>>> >> > num_completed_requests: 0, num_completed_flushes: 1
>>> >> > clientid: 1294542= num_caps: 13000, num_leases: 12,
>>> request_load_avg:
>>> >> 105,
>>> >> > num_completed_requests: 0, num_completed_flushes: 6
>>> >> > clientid: 1282187= num_caps: 16869, num_leases: 1,
>>> request_load_avg: 0,
>>> >> > num_completed_requests: 0, num_completed_flushes: 1
>>> >> > clientid: 1275589= num_caps: 18943, num_leases: 0,
>>> request_load_avg: 52,
>>> >> > num_completed_requests: 0, num_completed_flushes: 1
>>> >> > clientid: 1282154= num_caps: 24747, num_leases: 1,
>>> request_load_avg: 57,
>>> >> > num_completed_requests: 2, num_completed_flushes: 2
>>> >> > clientid: 1275553= num_caps: 25120, num_leases: 2,
>>> request_load_avg: 116,
>>> >> > num_completed_requests: 2, num_completed_flushes: 8
>>> >> > clientid: 1282142= num_caps: 27185, num_leases: 6,
>>> request_load_avg: 128,
>>> >> > num_completed_requests: 0, num_completed_flushes: 8
>>> >> > clientid: 1275535= num_caps: 40364, num_leases: 6,
>>> request_load_avg: 111,
>>> >> > num_completed_requests: 2, num_completed_flushes: 8
>>> >> > clientid: 1282130= num_caps: 41483, num_leases: 0,
>>> request_load_avg: 135,
>>> >> > num_completed_requests: 0, num_completed_flushes: 1
>>> >> > clientid: 1275547= num_caps: 42953, num_leases: 4,
>>> request_load_avg: 119,
>>> >> > num_completed_requests: 2, num_completed_flushes: 6
>>> >> > clientid: 1282139= num_caps: 45435, num_leases: 27,
>>> request_load_avg: 84,
>>> >> > num_completed_requests: 2, num_completed_flushes: 34
>>> >> > clientid: 1282136= num_caps: 48374, num_leases: 8,
>>> request_load_avg: 0,
>>> >> > num_completed_requests: 1, num_completed_flushes: 1
>>> >> > clientid: 1275532= num_caps: 48664, num_leases: 7,
>>> request_load_avg: 115,
>>> >> > num_completed_requests: 2, num_completed_flushes: 8
>>> >> > clientid: 1191789= num_caps: 130319, num_leases: 0,
>>> request_load_avg:
>>> >> 1753,
>>> >> > num_completed_requests: 0, num_completed_flushes: 0
>>> >> > clientid: 1275571= num_caps: 139488, num_leases: 0,
>>> request_load_avg: 2,
>>> >> > num_completed_requests: 0, num_completed_flushes: 1
>>> >> > clientid: 1282133= num_caps: 145487, num_leases: 0,
>>> request_load_avg: 8,
>>> >> > num_completed_requests: 1, num_completed_flushes: 1
>>> >> > clientid: 1534496= num_caps: 1041316, num_leases: 0,
>>> request_load_avg: 0,
>>> >> > num_completed_requests: 0, num_completed_flushes: 1
>>> >> >
>>> >> > ------------------------------
>>> >> > When I check the dashboard/service/mds I see %120+ CPU usage on
>>> active
>>> >> MDS
>>> >> > but on the host everything is almost idle and disk waits are very
>>> low.
>>> >> >
>>> >> > avg-cpu: %user %nice %system %iowait %steal %idle
>>> >> > 0.61 0.00 0.38 0.41 0.00 98.60
>>> >> >
>>> >> > Device r/s rMB/s rrqm/s %rrqm r_await rareq-sz
>>> w/s
>>> >> > wMB/s wrqm/s %wrqm w_await wareq-sz d/s dMB/s drqm/s
>>> >> %drqm
>>> >> > d_await dareq-sz f/s f_await aqu-sz %util
>>> >> > sdc 2.00 0.01 0.00 0.00 0.50 6.00
>>> 20.00
>>> >> > 0.04 0.00 0.00 0.50 2.00 0.00 0.00 0.00
>>> >> 0.00
>>> >> > 0.00 0.00 10.00 0.60 0.02 1.20
>>> >> > sdd 3.00 0.02 0.00 0.00 0.67 8.00
>>> 285.00
>>> >> > 1.84 77.00 21.27 0.44 6.61 0.00 0.00 0.00
>>> >> 0.00
>>> >> > 0.00 0.00 114.00 0.83 0.22 22.40
>>> >> > sde 1.00 0.01 0.00 0.00 1.00 8.00
>>> 36.00
>>> >> > 0.08 3.00 7.69 0.64 2.33 0.00 0.00 0.00
>>> >> 0.00
>>> >> > 0.00 0.00 18.00 0.67 0.04 1.60
>>> >> > sdf 5.00 0.04 0.00 0.00 0.40 7.20
>>> 40.00
>>> >> > 0.09 3.00 6.98 0.53 2.30 0.00 0.00 0.00
>>> >> 0.00
>>> >> > 0.00 0.00 20.00 0.70 0.04 2.00
>>> >> > sdg 11.00 0.08 0.00 0.00 0.73 7.27
>>> 36.00
>>> >> > 0.09 4.00 10.00 0.50 2.44 0.00 0.00 0.00
>>> >> 0.00
>>> >> > 0.00 0.00 18.00 0.72 0.04 3.20
>>> >> > sdh 5.00 0.03 0.00 0.00 0.60 5.60
>>> 46.00
>>> >> > 0.10 2.00 4.17 0.59 2.17 0.00 0.00 0.00
>>> >> 0.00
>>> >> > 0.00 0.00 23.00 0.83 0.05 2.80
>>> >> > sdi 7.00 0.04 0.00 0.00 0.43 6.29
>>> 36.00
>>> >> > 0.07 1.00 2.70 0.47 2.11 0.00 0.00 0.00
>>> >> 0.00
>>> >> > 0.00 0.00 18.00 0.61 0.03 2.40
>>> >> > sdj 5.00 0.04 0.00 0.00 0.80 7.20
>>> 42.00
>>> >> > 0.09 1.00 2.33 0.67 2.10 0.00 0.00 0.00
>>> >> 0.00
>>> >> > 0.00 0.00 21.00 0.81 0.05 3.20
>>> >> >
>>> >> > ------------------------------
>>> >> > Other than this 5x node cluster, I also have a 3x node cluster with
>>> >> > identical hardware but it serves for a different purpose and data
>>> >> workload.
>>> >> > In this cluster I don't have any problem and MDS default settings
>>> seems
>>> >> > enough.
>>> >> > The only difference between two cluster is, 5x node cluster used
>>> directly
>>> >> > by users, 3x node cluster used heavily to read and write data via
>>> >> projects
>>> >> > not by users. So allocate and de-allocate will be better.
>>> >> >
>>> >> > I guess I just have a problematic use case on the 5x node cluster
>>> and as
>>> >> I
>>> >> > mentioned above, I might have the similar problem but I don't know
>>> how to
>>> >> > debug it.
>>> >> >
>>> >> >
>>> >>
>>> https://lists.ceph.io/hyperkitty/list/ceph-users@xxxxxxx/thread/YO4SGL4DJQ6EKUBUIHKTFSW72ZJ3XLZS/
>>> >> > quote:"A user running VSCodium, keeping 15k caps open.. the
>>> opportunistic
>>> >> > caps recall eventually starts recalling those but the (el7 kernel)
>>> client
>>> >> > won't release them. Stopping Codium seems to be the only way to
>>> release."
>>> >> >
>>> >> > ------------------------------
>>> >> > Before reading the osd df you should know that I created 2x
>>> >> > OSD/per"CT4000MX500SSD1"
>>> >> > # ceph osd df tree
>>> >> > ID CLASS WEIGHT REWEIGHT SIZE RAW USE DATA OMAP
>>> >> META
>>> >> > AVAIL %USE VAR PGS STATUS TYPE NAME
>>> >> > -1 145.54321 - 146 TiB 45 TiB 44 TiB 119
>>> GiB 333
>>> >> > GiB 101 TiB 30.81 1.00 - root default
>>> >> > -3 29.10864 - 29 TiB 8.9 TiB 8.8 TiB 25
>>> GiB 66
>>> >> > GiB 20 TiB 30.54 0.99 - host ud-01
>>> >> > 0 ssd 1.81929 1.00000 1.8 TiB 616 GiB 610 GiB 1.4
>>> GiB 4.5
>>> >> > GiB 1.2 TiB 33.04 1.07 61 up osd.0
>>> >> > 1 ssd 1.81929 1.00000 1.8 TiB 527 GiB 521 GiB 1.5
>>> GiB 4.0
>>> >> > GiB 1.3 TiB 28.28 0.92 53 up osd.1
>>> >> > 2 ssd 1.81929 1.00000 1.8 TiB 595 GiB 589 GiB 2.3
>>> GiB 4.0
>>> >> > GiB 1.2 TiB 31.96 1.04 63 up osd.2
>>> >> > 3 ssd 1.81929 1.00000 1.8 TiB 527 GiB 521 GiB 1.8
>>> GiB 4.2
>>> >> > GiB 1.3 TiB 28.30 0.92 55 up osd.3
>>> >> > 4 ssd 1.81929 1.00000 1.8 TiB 525 GiB 520 GiB 1.3
>>> GiB 3.9
>>> >> > GiB 1.3 TiB 28.21 0.92 52 up osd.4
>>> >> > 5 ssd 1.81929 1.00000 1.8 TiB 592 GiB 586 GiB 1.8
>>> GiB 3.8
>>> >> > GiB 1.2 TiB 31.76 1.03 61 up osd.5
>>> >> > 6 ssd 1.81929 1.00000 1.8 TiB 559 GiB 553 GiB 1.8
>>> GiB 4.3
>>> >> > GiB 1.3 TiB 30.03 0.97 57 up osd.6
>>> >> > 7 ssd 1.81929 1.00000 1.8 TiB 602 GiB 597 GiB 836
>>> MiB 4.4
>>> >> > GiB 1.2 TiB 32.32 1.05 58 up osd.7
>>> >> > 8 ssd 1.81929 1.00000 1.8 TiB 614 GiB 609 GiB 1.2
>>> GiB 4.5
>>> >> > GiB 1.2 TiB 32.98 1.07 60 up osd.8
>>> >> > 9 ssd 1.81929 1.00000 1.8 TiB 571 GiB 565 GiB 2.2
>>> GiB 4.2
>>> >> > GiB 1.3 TiB 30.67 1.00 61 up osd.9
>>> >> > 10 ssd 1.81929 1.00000 1.8 TiB 528 GiB 522 GiB 1.3
>>> GiB 4.1
>>> >> > GiB 1.3 TiB 28.33 0.92 52 up osd.10
>>> >> > 11 ssd 1.81929 1.00000 1.8 TiB 551 GiB 546 GiB 1.5
>>> GiB 3.6
>>> >> > GiB 1.3 TiB 29.57 0.96 56 up osd.11
>>> >> > 12 ssd 1.81929 1.00000 1.8 TiB 594 GiB 588 GiB 1.8
>>> GiB 4.4
>>> >> > GiB 1.2 TiB 31.91 1.04 61 up osd.12
>>> >> > 13 ssd 1.81929 1.00000 1.8 TiB 561 GiB 555 GiB 1.1
>>> GiB 4.3
>>> >> > GiB 1.3 TiB 30.10 0.98 55 up osd.13
>>> >> > 14 ssd 1.81929 1.00000 1.8 TiB 616 GiB 609 GiB 1.9
>>> GiB 4.2
>>> >> > GiB 1.2 TiB 33.04 1.07 64 up osd.14
>>> >> > 15 ssd 1.81929 1.00000 1.8 TiB 525 GiB 520 GiB 1.1
>>> GiB 4.0
>>> >> > GiB 1.3 TiB 28.20 0.92 51 up osd.15
>>> >> > -5 29.10864 - 29 TiB 9.0 TiB 8.9 TiB 22
>>> GiB 67
>>> >> > GiB 20 TiB 30.89 1.00 - host ud-02
>>> >> > 16 ssd 1.81929 1.00000 1.8 TiB 617 GiB 611 GiB 1.7
>>> GiB 4.7
>>> >> > GiB 1.2 TiB 33.12 1.08 63 up osd.16
>>> >> > 17 ssd 1.81929 1.00000 1.8 TiB 582 GiB 577 GiB 1.6
>>> GiB 4.0
>>> >> > GiB 1.3 TiB 31.26 1.01 59 up osd.17
>>> >> > 18 ssd 1.81929 1.00000 1.8 TiB 583 GiB 578 GiB 418
>>> MiB 4.0
>>> >> > GiB 1.3 TiB 31.29 1.02 54 up osd.18
>>> >> > 19 ssd 1.81929 1.00000 1.8 TiB 550 GiB 544 GiB 1.5
>>> GiB 4.0
>>> >> > GiB 1.3 TiB 29.50 0.96 56 up osd.19
>>> >> > 20 ssd 1.81929 1.00000 1.8 TiB 551 GiB 546 GiB 1.1
>>> GiB 4.1
>>> >> > GiB 1.3 TiB 29.57 0.96 54 up osd.20
>>> >> > 21 ssd 1.81929 1.00000 1.8 TiB 616 GiB 610 GiB 1.3
>>> GiB 4.4
>>> >> > GiB 1.2 TiB 33.04 1.07 60 up osd.21
>>> >> > 22 ssd 1.81929 1.00000 1.8 TiB 573 GiB 567 GiB 1.6
>>> GiB 4.1
>>> >> > GiB 1.3 TiB 30.75 1.00 58 up osd.22
>>> >> > 23 ssd 1.81929 1.00000 1.8 TiB 616 GiB 610 GiB 1.3
>>> GiB 4.3
>>> >> > GiB 1.2 TiB 33.06 1.07 60 up osd.23
>>> >> > 24 ssd 1.81929 1.00000 1.8 TiB 539 GiB 534 GiB 844
>>> MiB 3.8
>>> >> > GiB 1.3 TiB 28.92 0.94 51 up osd.24
>>> >> > 25 ssd 1.81929 1.00000 1.8 TiB 583 GiB 576 GiB 2.1
>>> GiB 4.1
>>> >> > GiB 1.3 TiB 31.27 1.02 61 up osd.25
>>> >> > 26 ssd 1.81929 1.00000 1.8 TiB 617 GiB 611 GiB 1.3
>>> GiB 4.6
>>> >> > GiB 1.2 TiB 33.12 1.08 61 up osd.26
>>> >> > 27 ssd 1.81929 1.00000 1.8 TiB 537 GiB 532 GiB 1.2
>>> GiB 4.1
>>> >> > GiB 1.3 TiB 28.84 0.94 53 up osd.27
>>> >> > 28 ssd 1.81929 1.00000 1.8 TiB 527 GiB 522 GiB 1.3
>>> GiB 4.2
>>> >> > GiB 1.3 TiB 28.29 0.92 53 up osd.28
>>> >> > 29 ssd 1.81929 1.00000 1.8 TiB 594 GiB 588 GiB 1.5
>>> GiB 4.6
>>> >> > GiB 1.2 TiB 31.91 1.04 59 up osd.29
>>> >> > 30 ssd 1.81929 1.00000 1.8 TiB 528 GiB 523 GiB 1.4
>>> GiB 4.1
>>> >> > GiB 1.3 TiB 28.35 0.92 53 up osd.30
>>> >> > 31 ssd 1.81929 1.00000 1.8 TiB 594 GiB 589 GiB 1.6
>>> GiB 3.8
>>> >> > GiB 1.2 TiB 31.89 1.03 61 up osd.31
>>> >> > -7 29.10864 - 29 TiB 8.9 TiB 8.8 TiB 23
>>> GiB 67
>>> >> > GiB 20 TiB 30.66 1.00 - host ud-03
>>> >> > 32 ssd 1.81929 1.00000 1.8 TiB 593 GiB 588 GiB 1.1
>>> GiB 4.3
>>> >> > GiB 1.2 TiB 31.84 1.03 57 up osd.32
>>> >> > 33 ssd 1.81929 1.00000 1.8 TiB 617 GiB 611 GiB 1.8
>>> GiB 4.4
>>> >> > GiB 1.2 TiB 33.13 1.08 63 up osd.33
>>> >> > 34 ssd 1.81929 1.00000 1.8 TiB 537 GiB 532 GiB 2.0
>>> GiB 3.8
>>> >> > GiB 1.3 TiB 28.84 0.94 59 up osd.34
>>> >> > 35 ssd 1.81929 1.00000 1.8 TiB 562 GiB 556 GiB 1.7
>>> GiB 4.2
>>> >> > GiB 1.3 TiB 30.16 0.98 58 up osd.35
>>> >> > 36 ssd 1.81929 1.00000 1.8 TiB 529 GiB 523 GiB 1.3
>>> GiB 3.9
>>> >> > GiB 1.3 TiB 28.38 0.92 52 up osd.36
>>> >> > 37 ssd 1.81929 1.00000 1.8 TiB 527 GiB 521 GiB 1.7
>>> GiB 4.2
>>> >> > GiB 1.3 TiB 28.28 0.92 55 up osd.37
>>> >> > 38 ssd 1.81929 1.00000 1.8 TiB 574 GiB 568 GiB 1.2
>>> GiB 4.3
>>> >> > GiB 1.3 TiB 30.79 1.00 55 up osd.38
>>> >> > 39 ssd 1.81929 1.00000 1.8 TiB 605 GiB 599 GiB 1.6
>>> GiB 4.2
>>> >> > GiB 1.2 TiB 32.48 1.05 61 up osd.39
>>> >> > 40 ssd 1.81929 1.00000 1.8 TiB 573 GiB 567 GiB 1.2
>>> GiB 4.4
>>> >> > GiB 1.3 TiB 30.76 1.00 56 up osd.40
>>> >> > 41 ssd 1.81929 1.00000 1.8 TiB 526 GiB 520 GiB 1.7
>>> GiB 3.9
>>> >> > GiB 1.3 TiB 28.21 0.92 54 up osd.41
>>> >> > 42 ssd 1.81929 1.00000 1.8 TiB 613 GiB 608 GiB 1010
>>> MiB 4.4
>>> >> > GiB 1.2 TiB 32.91 1.07 58 up osd.42
>>> >> > 43 ssd 1.81929 1.00000 1.8 TiB 606 GiB 600 GiB 1.7
>>> GiB 4.3
>>> >> > GiB 1.2 TiB 32.51 1.06 61 up osd.43
>>> >> > 44 ssd 1.81929 1.00000 1.8 TiB 583 GiB 577 GiB 1.6
>>> GiB 4.2
>>> >> > GiB 1.3 TiB 31.29 1.02 60 up osd.44
>>> >> > 45 ssd 1.81929 1.00000 1.8 TiB 618 GiB 613 GiB 1.4
>>> GiB 4.3
>>> >> > GiB 1.2 TiB 33.18 1.08 62 up osd.45
>>> >> > 46 ssd 1.81929 1.00000 1.8 TiB 550 GiB 544 GiB 1.5
>>> GiB 4.2
>>> >> > GiB 1.3 TiB 29.50 0.96 54 up osd.46
>>> >> > 47 ssd 1.81929 1.00000 1.8 TiB 526 GiB 522 GiB 692
>>> MiB 3.7
>>> >> > GiB 1.3 TiB 28.25 0.92 50 up osd.47
>>> >> > -9 29.10864 - 29 TiB 9.0 TiB 8.9 TiB 26
>>> GiB 68
>>> >> > GiB 20 TiB 31.04 1.01 - host ud-04
>>> >> > 48 ssd 1.81929 1.00000 1.8 TiB 540 GiB 534 GiB 2.2
>>> GiB 3.6
>>> >> > GiB 1.3 TiB 28.96 0.94 58 up osd.48
>>> >> > 49 ssd 1.81929 1.00000 1.8 TiB 617 GiB 611 GiB 1.4
>>> GiB 4.5
>>> >> > GiB 1.2 TiB 33.11 1.07 61 up osd.49
>>> >> > 50 ssd 1.81929 1.00000 1.8 TiB 618 GiB 612 GiB 1.2
>>> GiB 4.8
>>> >> > GiB 1.2 TiB 33.17 1.08 61 up osd.50
>>> >> > 51 ssd 1.81929 1.00000 1.8 TiB 618 GiB 612 GiB 1.5
>>> GiB 4.5
>>> >> > GiB 1.2 TiB 33.19 1.08 61 up osd.51
>>> >> > 52 ssd 1.81929 1.00000 1.8 TiB 526 GiB 521 GiB 1.4
>>> GiB 4.1
>>> >> > GiB 1.3 TiB 28.25 0.92 53 up osd.52
>>> >> > 53 ssd 1.81929 1.00000 1.8 TiB 618 GiB 611 GiB 2.4
>>> GiB 4.3
>>> >> > GiB 1.2 TiB 33.17 1.08 66 up osd.53
>>> >> > 54 ssd 1.81929 1.00000 1.8 TiB 550 GiB 544 GiB 1.5
>>> GiB 4.3
>>> >> > GiB 1.3 TiB 29.54 0.96 55 up osd.54
>>> >> > 55 ssd 1.81929 1.00000 1.8 TiB 527 GiB 522 GiB 1.3
>>> GiB 4.0
>>> >> > GiB 1.3 TiB 28.29 0.92 52 up osd.55
>>> >> > 56 ssd 1.81929 1.00000 1.8 TiB 525 GiB 519 GiB 1.2
>>> GiB 4.1
>>> >> > GiB 1.3 TiB 28.16 0.91 52 up osd.56
>>> >> > 57 ssd 1.81929 1.00000 1.8 TiB 615 GiB 609 GiB 2.3
>>> GiB 4.2
>>> >> > GiB 1.2 TiB 33.03 1.07 65 up osd.57
>>> >> > 58 ssd 1.81929 1.00000 1.8 TiB 527 GiB 522 GiB 1.6
>>> GiB 3.7
>>> >> > GiB 1.3 TiB 28.31 0.92 55 up osd.58
>>> >> > 59 ssd 1.81929 1.00000 1.8 TiB 615 GiB 609 GiB 1.2
>>> GiB 4.6
>>> >> > GiB 1.2 TiB 33.01 1.07 60 up osd.59
>>> >> > 60 ssd 1.81929 1.00000 1.8 TiB 594 GiB 588 GiB 1.2
>>> GiB 4.4
>>> >> > GiB 1.2 TiB 31.88 1.03 59 up osd.60
>>> >> > 61 ssd 1.81929 1.00000 1.8 TiB 616 GiB 610 GiB 1.9
>>> GiB 4.1
>>> >> > GiB 1.2 TiB 33.04 1.07 64 up osd.61
>>> >> > 62 ssd 1.81929 1.00000 1.8 TiB 620 GiB 614 GiB 1.9
>>> GiB 4.4
>>> >> > GiB 1.2 TiB 33.27 1.08 63 up osd.62
>>> >> > 63 ssd 1.81929 1.00000 1.8 TiB 527 GiB 522 GiB 1.5
>>> GiB 4.0
>>> >> > GiB 1.3 TiB 28.30 0.92 53 up osd.63
>>> >> > -11 29.10864 - 29 TiB 9.0 TiB 8.9 TiB 23
>>> GiB 65
>>> >> > GiB 20 TiB 30.91 1.00 - host ud-05
>>> >> > 64 ssd 1.81929 1.00000 1.8 TiB 608 GiB 601 GiB 2.3
>>> GiB 4.5
>>> >> > GiB 1.2 TiB 32.62 1.06 65 up osd.64
>>> >> > 65 ssd 1.81929 1.00000 1.8 TiB 606 GiB 601 GiB 628
>>> MiB 4.2
>>> >> > GiB 1.2 TiB 32.53 1.06 57 up osd.65
>>> >> > 66 ssd 1.81929 1.00000 1.8 TiB 583 GiB 578 GiB 1.3
>>> GiB 4.3
>>> >> > GiB 1.2 TiB 31.31 1.02 57 up osd.66
>>> >> > 67 ssd 1.81929 1.00000 1.8 TiB 537 GiB 533 GiB 436
>>> MiB 3.6
>>> >> > GiB 1.3 TiB 28.82 0.94 50 up osd.67
>>> >> > 68 ssd 1.81929 1.00000 1.8 TiB 541 GiB 535 GiB 2.5
>>> GiB 3.8
>>> >> > GiB 1.3 TiB 29.04 0.94 59 up osd.68
>>> >> > 69 ssd 1.81929 1.00000 1.8 TiB 606 GiB 601 GiB 1.1
>>> GiB 4.4
>>> >> > GiB 1.2 TiB 32.55 1.06 59 up osd.69
>>> >> > 70 ssd 1.81929 1.00000 1.8 TiB 604 GiB 598 GiB 1.8
>>> GiB 4.1
>>> >> > GiB 1.2 TiB 32.44 1.05 63 up osd.70
>>> >> > 71 ssd 1.81929 1.00000 1.8 TiB 606 GiB 600 GiB 1.9
>>> GiB 4.5
>>> >> > GiB 1.2 TiB 32.53 1.06 62 up osd.71
>>> >> > 72 ssd 1.81929 1.00000 1.8 TiB 602 GiB 598 GiB 612
>>> MiB 4.1
>>> >> > GiB 1.2 TiB 32.33 1.05 57 up osd.72
>>> >> > 73 ssd 1.81929 1.00000 1.8 TiB 571 GiB 565 GiB 1.8
>>> GiB 4.5
>>> >> > GiB 1.3 TiB 30.65 0.99 58 up osd.73
>>> >> > 74 ssd 1.81929 1.00000 1.8 TiB 608 GiB 602 GiB 1.8
>>> GiB 4.2
>>> >> > GiB 1.2 TiB 32.62 1.06 61 up osd.74
>>> >> > 75 ssd 1.81929 1.00000 1.8 TiB 536 GiB 531 GiB 1.9
>>> GiB 3.5
>>> >> > GiB 1.3 TiB 28.80 0.93 57 up osd.75
>>> >> > 76 ssd 1.81929 1.00000 1.8 TiB 605 GiB 599 GiB 1.4
>>> GiB 4.5
>>> >> > GiB 1.2 TiB 32.48 1.05 60 up osd.76
>>> >> > 77 ssd 1.81929 1.00000 1.8 TiB 537 GiB 532 GiB 1.2
>>> GiB 3.9
>>> >> > GiB 1.3 TiB 28.84 0.94 52 up osd.77
>>> >> > 78 ssd 1.81929 1.00000 1.8 TiB 525 GiB 520 GiB 1.3
>>> GiB 3.8
>>> >> > GiB 1.3 TiB 28.20 0.92 52 up osd.78
>>> >> > 79 ssd 1.81929 1.00000 1.8 TiB 536 GiB 531 GiB 1.1
>>> GiB 3.3
>>> >> > GiB 1.3 TiB 28.76 0.93 53 up osd.79
>>> >> > TOTAL 146 TiB 45 TiB 44 TiB 119
>>> GiB 333
>>> >> > GiB 101 TiB 30.81
>>> >> > MIN/MAX VAR: 0.91/1.08 STDDEV: 1.90
>>> >> >
>>> >> >
>>> >> >
>>> >> > Eugen Block <eblock@xxxxxx>, 25 Oca 2024 Per, 16:52 tarihinde şunu
>>> >> yazdı:
>>> >> >
>>> >> >> There is no definitive answer wrt mds tuning. As it is everywhere
>>> >> >> mentioned, it's about finding the right setup for your specific
>>> >> >> workload. If you can synthesize your workload (maybe scale down a
>>> bit)
>>> >> >> try optimizing it in a test cluster without interrupting your
>>> >> >> developers too much.
>>> >> >> But what you haven't explained yet is what are you experiencing as
>>> a
>>> >> >> performance issue? Do you have numbers or a detailed description?
>>> >> >> From the fs status output you didn't seem to have too much
>>> activity
>>> >> >> going on (around 140 requests per second), but that's probably not
>>> the
>>> >> >> usual traffic? What does ceph report in its client IO output?
>>> >> >> Can you paste the 'ceph osd df' output as well?
>>> >> >> Do you have dedicated MDS servers or are they colocated with other
>>> >> >> services?
>>> >> >>
>>> >> >> Zitat von Özkan Göksu <ozkangksu@xxxxxxxxx>:
>>> >> >>
>>> >> >> > Hello Eugen.
>>> >> >> >
>>> >> >> > I read all of your MDS related topics and thank you so much for
>>> your
>>> >> >> effort
>>> >> >> > on this.
>>> >> >> > There is not much information and I couldn't find a MDS tuning
>>> guide
>>> >> at
>>> >> >> > all. It seems that you are the correct person to discuss mds
>>> >> debugging
>>> >> >> and
>>> >> >> > tuning.
>>> >> >> >
>>> >> >> > Do you have any documents or may I learn what is the proper way
>>> to
>>> >> debug
>>> >> >> > MDS and clients ?
>>> >> >> > Which debug logs will guide me to understand the limitations and
>>> will
>>> >> >> help
>>> >> >> > to tune according to the data flow?
>>> >> >> >
>>> >> >> > While searching, I find this:
>>> >> >> >
>>> >> >>
>>> >>
>>> https://lists.ceph.io/hyperkitty/list/ceph-users@xxxxxxx/thread/YO4SGL4DJQ6EKUBUIHKTFSW72ZJ3XLZS/
>>> >> >> > quote:"A user running VSCodium, keeping 15k caps open.. the
>>> >> opportunistic
>>> >> >> > caps recall eventually starts recalling those but the (el7
>>> kernel)
>>> >> client
>>> >> >> > won't release them. Stopping Codium seems to be the only way to
>>> >> release."
>>> >> >> >
>>> >> >> > Because of this I think I also need to play around with the
>>> client
>>> >> side
>>> >> >> too.
>>> >> >> >
>>> >> >> > My main goal is increasing the speed and reducing the latency
>>> and I
>>> >> >> wonder
>>> >> >> > if these ideas are correct or not:
>>> >> >> > - Maybe I need to increase client side cache size because via
>>> each
>>> >> >> client,
>>> >> >> > multiple users request a lot of objects and clearly the
>>> >> >> > client_cache_size=16 default is not enough.
>>> >> >> > - Maybe I need to increase client side maximum cache limit for
>>> >> >> > object "client_oc_max_objects=1000 to 10000" and data
>>> >> >> "client_oc_size=200mi
>>> >> >> > to 400mi"
>>> >> >> > - The client cache cleaning threshold is not aggressive enough
>>> to keep
>>> >> >> the
>>> >> >> > free cache size in the desired range. I need to make it
>>> aggressive but
>>> >> >> this
>>> >> >> > should not reduce speed and increase latency.
>>> >> >> >
>>> >> >> > mds_cache_memory_limit=4gi to 16gi
>>> >> >> > client_oc_max_objects=1000 to 10000
>>> >> >> > client_oc_size=200mi to 400mi
>>> >> >> > client_permissions=false #to reduce latency.
>>> >> >> > client_cache_size=16 to 128
>>> >> >> >
>>> >> >> >
>>> >> >> > What do you think?
>>> >> >>
>>> >> >>
>>> >> >>
>>> >> >>
>>> >>
>>> >>
>>> >>
>>> >>
>>>
>>>
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>>>
>>
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