Increasing day by day, this is the current situation: (1 server has 6x 15.3TB SAS ssds, 3x ssds are using 1x 1.92TB nvme for db+wal.
WRN] BLUEFS_SPILLOVER: 13 OSD(s) experiencing BlueFS spillover
osd.1 spilled over 56 GiB metadata from 'db' device (318 GiB used of 596 GiB) to slow device
osd.5 spilled over 34 GiB metadata from 'db' device (316 GiB used of 596 GiB) to slow device
osd.6 spilled over 37 GiB metadata from 'db' device (314 GiB used of 596 GiB) to slow device
osd.8 spilled over 121 MiB metadata from 'db' device (317 GiB used of 596 GiB) to slow device
osd.9 spilled over 53 GiB metadata from 'db' device (316 GiB used of 596 GiB) to slow device
osd.10 spilled over 114 GiB metadata from 'db' device (307 GiB used of 596 GiB) to slow device
osd.11 spilled over 68 GiB metadata from 'db' device (315 GiB used of 596 GiB) to slow device
osd.13 spilled over 30 GiB metadata from 'db' device (315 GiB used of 596 GiB) to slow device
osd.15 spilled over 65 GiB metadata from 'db' device (313 GiB used of 596 GiB) to slow device
osd.21 spilled over 6.8 GiB metadata from 'db' device (298 GiB used of 596 GiB) to slow device
osd.22 spilled over 23 GiB metadata from 'db' device (317 GiB used of 596 GiB) to slow device
osd.27 spilled over 228 GiB metadata from 'db' device (292 GiB used of 596 GiB) to slow device
osd.34 spilled over 9.8 GiB metadata from 'db' device (316 GiB used of 596 GiB) to slow device
I guess it’s not an issue because it spilled over to an ssd from an nvme which is running on 100% unfortunately. It would have effect I guess more if spillover to hdd. Or can I scare anything with spillover?
I have 6 nodes with this setup, I can’t believe that 30k read and 10-15k write iops less than 1GB throughput can max out this cluster with ec 4:2 :((
Istvan Szabo
Senior Infrastructure Engineer
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Agoda Services Co., Ltd.
e: istvan.szabo@xxxxxxxxx<mailto:istvan.szabo@xxxxxxxxx>
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On 2021. Sep 21., at 20:21, Christian Wuerdig <christian.wuerdig@xxxxxxxxx> wrote:
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On Wed, 22 Sept 2021 at 05:54, Szabo, Istvan (Agoda)
<Istvan.Szabo@xxxxxxxxx> wrote:
Sorry to steal it, so if I have 500GB and 700GB mixed wal+rocksdb on nvme the number should be the level base 5000000000 and 7000000000? Or needs to be power of 2?
Generally the sum of all levels (up to the max of your metadata) needs
to fit into the db partition for each OSD. If you have a 500 or 700 GB
WAL+DB partition per OSD then the default settings should carry you to
L3 (~333GB required free space). Do you have more than 300GB metadata
per OSD?
All examples I've ever seen show the level base size at a power of 2
but I don't know if there are any side effects not doing that
5/7GB level base is an order of magnitude higher than the default and
it's unclear what performance effect this has.
I would not advise tinkering with the defaults unless you have a lot
of time and energy to burn on testing and are willing to accept
potential future performance issues on upgrade because you run a setup
that nobody ever tests for.
What's the size of your OSDs, how much db space per OSD do you
actually have and what do the spillover warnings say?
Istvan Szabo
Senior Infrastructure Engineer
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Agoda Services Co., Ltd.
e: istvan.szabo@xxxxxxxxx
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On 2021. Sep 21., at 9:19, Christian Wuerdig <christian.wuerdig@xxxxxxxxx> wrote:
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It's been discussed a few times on the list but RocksDB levels essentially
grow by a factor of 10 (max_bytes_for_level_multiplier) by default and you
need (level-1)*10 space for the next level on your drive to avoid spill over
So the sequence (by default) is 256MB -> 2.56GB -> 25.6GB -> 256GB GB and
since 50GB < 286 (sum of all levels) you get spill-over going from L2 to
L3. See also
https://docs.ceph.com/en/latest/rados/configuration/bluestore-config-ref/#sizing
Interestingly your level base seems to be 512MB instead of the default
256MB - did you change that? In your case the sequence I would have
expected is 0.5 -> 5 -> 50 - and you should have already seen spillover at
5GB (since you only have 50GB partitions but you need 55.5GB at least)
Not sure what's up with that. I think you need to re-create OSDs after
changing these RocksDB params
Overall since Pacific this no longer holds entirely true since RocksDB
sharding was added (
https://docs.ceph.com/en/latest/rados/configuration/bluestore-config-ref/#bluestore-rocksdb-sharding)
- it was broken in 16.2.4 but looks like it's fixed in 16.2.6
1. Upgrade to Pacific
2. Get rid of the NVME raid
3. Make 160GB DB partitions
4. Activate RocksDB sharding
5. Don't worry about RocksDB params
If you don't feel like upgrading to Pacific any time soon but want to make
more efficient use of the NVME and don't mind going out on a limp I'd still
do 2+3 plus study
https://github-wiki-see.page/m/facebook/rocksdb/wiki/Leveled-Compaction
carefully and make adjustments based on that.
With 160GB partitions a multiplier of 7 might work well with a base size of
350MB 0.35 -> 2.45 -> 17.15 -> 120.05 (total 140GB out of 160GB)
You could also try to switch to a 9x multiplier and re-create one of the
OSDs to see how it pans out prior to dissolving the raid1 setup (given your
settings that should result in 0.5 -> 4.5 -> 40.5 GB usage)
On Tue, 21 Sept 2021 at 13:19, mhnx <morphinwithyou@xxxxxxxxx> wrote:
Hello everyone!
I want to understand the concept and tune my rocksDB options on nautilus
14.2.16.
osd.178 spilled over 102 GiB metadata from 'db' device (24 GiB used of
50 GiB) to slow device
osd.180 spilled over 91 GiB metadata from 'db' device (33 GiB used of
50 GiB) to slow device
The problem is, I have the spill over warnings like the rest of the
community.
I tuned RocksDB Options with the settings below but the problem still
exists and I wonder if I did anything wrong. I still have the Spill Overs
and also some times index SSD's are getting down due to compaction problems
and can not start them until I do offline compaction.
Let me tell you about my hardware right?
Every server in my system has:
HDD - 19 x TOSHIBA MG08SCA16TEY 16.0TB for EC pool.
SSD - 3 x SAMSUNG MZILS960HEHP/007 GXL0 960GB
NVME - 2 x PM1725b 1.6TB
I'm using Raid 1 Nvme for Bluestore DB. I dont have WAL.
19*50GB = 950GB total usage on NVME. (I was thinking use the rest but
regret it now)
So! Finally let's check my RocksDB Options:
[osd]
bluefs_buffered_io = true
bluestore_rocksdb_options =
compression=kNoCompression,max_write_buffer_number=32,min_write_buffer_number_to_merge=2,recycle_log_file_num=32,compaction_style=kCompactionStyleLevel,write_buffer_size=67108864,target_file_size_base=67108864,max_background_compactions=31,level0_file_num_compaction_trigger=8,level0_slowdown_writes_trigger=32,level0_stop_writes_trigger=64,flusher_threads=8,compaction_readahead_size=2MB,compaction_threads=16,
*max_bytes_for_level_base=536870912*,
*max_bytes_for_level_multiplier=10*
*"ceph osd df tree" *to see ssd and hdd usage, omap and meta.
ID CLASS WEIGHT REWEIGHT SIZE RAW USE DATA OMAP META
AVAIL %USE VAR PGS STATUS TYPE NAME
-28 280.04810 - 280 TiB 169 TiB 166 TiB 688 GiB 2.4 TiB 111
TiB 60.40 1.00 - host MHNX1
178 hdd 14.60149 1.00000 15 TiB 8.6 TiB 8.5 TiB 44 KiB 126 GiB 6.0
TiB 59.21 0.98 174 up osd.178
179 ssd 0.87329 1.00000 894 GiB 415 GiB 89 GiB 321 GiB 5.4 GiB 479
GiB 46.46 0.77 104 up osd.179
I know the size of NVME is not suitable for 16TB HDD's. I should have more
but the expense is cutting us pieces. Because of that I think I'll see the
spill overs no matter what I do. But maybe I will make it better
with your help!
*My questions are:*
1- What is the meaning of (33 GiB used of 50 GiB)
2- Why it's not 50GiB / 50GiB ?
3- Do I have 17GiB unused area on the DB partition?
4- Is there anything wrong with my Rocksdb options?
5- How can I be sure and find the good Rocksdb Options for Ceph?
6- How can I measure the change and test it?
7- Do I need different RocksDB options for HDD's and SSD's ?
8- If I stop using Nvme Raid1 to gain x2 size and resize the DB's to
160GiB. Is it worth to take Nvme faulty? Because I will lose 10HDD at the
same time but I have 10 Node and that's only %5 of the EC data . I use m=8
k=2.
P.S: There are so many people asking and searching around this. I hope it
will work this time.
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