Re: RBD Block performance vs rbd mount as filesystem

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On Mon, 7 Nov 2016 07:46:16 +0100 (CET) Alexandre DERUMIER wrote:

[snip]
> >>and it looks disable cephx auth is no good for production use.... cephx affect lot of performance? 
> 
> for me, I still have 10-20% difference with cephx.
> If you only use your ceph cluster for your qemu cluster, I don't see any problem to disable it.
> (and of course your ceph cluster is firewalled / or network access is only available for your qemu client).
> 
Yup, most people with production cluster will have a setup like that.

> Note that changing it only is not possible. so you need to shutdown all the clients before doing this change.
>
And this is why I'll never be able to disable it on any production
cluster, only new ones will get that benefit. ^o^

Christian
 
> 
> 
> ----- Mail original -----
> De: "Bill WONG" <wongahshuen@xxxxxxxxx>
> À: "aderumier" <aderumier@xxxxxxxxx>
> Cc: "dillaman" <dillaman@xxxxxxxxxx>, "ceph-users" <ceph-users@xxxxxxxxxxxxxx>
> Envoyé: Lundi 7 Novembre 2016 06:35:38
> Objet: Re:  RBD Block performance vs rbd mount as filesystem
> 
> HI Alexandre, 
> thank you! 
> any document can provided for how i can complied ceph with jemalloc as well? as it looks if ceph with jemalloc is much better performance too. 
> and what's the side effect if debug ms=0/0 and it looks disable cephx auth is no good for production use.... cephx affect lot of performance? 
> 
> 
> On Sat, Nov 5, 2016 at 5:55 PM, Alexandre DERUMIER < [ mailto:aderumier@xxxxxxxxx | aderumier@xxxxxxxxx ] > wrote: 
> 
> 
> here some tips I use to improve librbd performance && qemu: 
> 
> - disabling cephx auth 
> 
> - disable debug_ms : (I'm jumping from 30k iops to 45k iops, with 4k randread) 
> 
> [global] 
> 
> debug ms = 0/0 
> 
> 
> - compile qemu with jemalloc (--enable-jemalloc) 
> [ https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg05265.html | https://lists.gnu.org/archive/html/qemu-devel/2015-06/msg05265.html ] 
> 
> 
> 
> ----- Mail original ----- 
> De: "Jason Dillaman" < [ mailto:jdillama@xxxxxxxxxx | jdillama@xxxxxxxxxx ] > 
> À: "Bill WONG" < [ mailto:wongahshuen@xxxxxxxxx | wongahshuen@xxxxxxxxx ] > 
> Cc: "aderumier" < [ mailto:aderumier@xxxxxxxxx | aderumier@xxxxxxxxx ] >, "ceph-users" < [ mailto:ceph-users@xxxxxxxxxxxxxx | ceph-users@xxxxxxxxxxxxxx ] > 
> Envoyé: Mardi 1 Novembre 2016 02:06:22 
> Objet: Re:  RBD Block performance vs rbd mount as filesystem 
> 
> For better or worse, I can repeat your "ioping" findings against a 
> qcow2 image hosted on a krbd-backed volume. The "bad" news is that it 
> actually isn't even sending any data to the OSDs -- which is why your 
> latency is shockingly low. When performing a "dd ... oflag=dsync" 
> against the krbd-backed qcow2 image, I can see lots of IO being 
> coalesced from 4K writes into larger writes, which is artificially 
> inflating the stats. 
> 
> 
> 
> On Mon, Oct 31, 2016 at 11:08 AM, Bill WONG < [ mailto:wongahshuen@xxxxxxxxx | wongahshuen@xxxxxxxxx ] > wrote: 
> > Hi Jason, 
> > 
> > it looks the situation is the same, no difference. my ceph.conf is below, 
> > any comments or improvement required? 
> > --- 
> > [global] 
> > fsid = 106a12b0-5ed0-4a71-b6aa-68a09088ec33 
> > mon_initial_members = ceph-mon1, ceph-mon2, ceph-mon3 
> > mon_host = 192.168.8.11,192.168.8.12,192.168.8.13 
> > auth_cluster_required = cephx 
> > auth_service_required = cephx 
> > auth_client_required = cephx 
> > filestore_xattr_use_omap = true 
> > osd pool default size = 3 
> > osd pool default min size = 1 
> > osd pool default pg num = 4096 
> > osd pool default pgp num = 4096 
> > osd_crush_chooseleaf_type = 1 
> > mon_pg_warn_max_per_osd = 0 
> > max_open_files = 131072 
> > 
> > [mon] 
> > mon_data = /var/lib/ceph/mon/ceph-$id 
> > 
> > mon clock drift allowed = 2 
> > mon clock drift warn backoff = 30 
> > 
> > [osd] 
> > osd_data = /var/lib/ceph/osd/ceph-$id 
> > osd_journal_size = 20000 
> > osd_mkfs_type = xfs 
> > osd_mkfs_options_xfs = -f 
> > filestore_xattr_use_omap = true 
> > filestore_min_sync_interval = 10 
> > filestore_max_sync_interval = 15 
> > filestore_queue_max_ops = 25000 
> > filestore_queue_max_bytes = 10485760 
> > filestore_queue_committing_max_ops = 5000 
> > filestore_queue_committing_max_bytes = 10485760000 
> > journal_max_write_bytes = 1073714824 
> > journal_max_write_entries = 10000 
> > journal_queue_max_ops = 50000 
> > journal_queue_max_bytes = 10485760000 
> > osd_max_write_size = 512 
> > osd_client_message_size_cap = 2147483648 
> > osd_deep_scrub_stride = 131072 
> > osd_op_threads = 8 
> > osd_disk_threads = 4 
> > osd_map_cache_size = 1024 
> > osd_map_cache_bl_size = 128 
> > osd_mount_options_xfs = "rw,noexec,nodev,noatime,nodiratime,nobarrier" 
> > osd_recovery_op_priority = 4 
> > osd_recovery_max_active = 10 
> > osd_max_backfills = 4 
> > rbd non blocking aio = false 
> > 
> > [client] 
> > rbd_cache = true 
> > rbd_cache_size = 268435456 
> > rbd_cache_max_dirty = 134217728 
> > rbd_cache_max_dirty_age = 5 
> > --- 
> > 
> > 
> > 
> > On Mon, Oct 31, 2016 at 9:20 PM, Jason Dillaman < [ mailto:jdillama@xxxxxxxxxx | jdillama@xxxxxxxxxx ] > wrote: 
> >> 
> >> On Sun, Oct 30, 2016 at 5:40 AM, Bill WONG < [ mailto:wongahshuen@xxxxxxxxx | wongahshuen@xxxxxxxxx ] > wrote: 
> >> > any ideas or comments? 
> >> 
> >> Can you set "rbd non blocking aio = false" in your ceph.conf and retry 
> >> librbd? This will eliminate at least one context switch on the read IO 
> >> path -- which result in increased latency under extremely low queue 
> >> depths. 
> >> 
> >> -- 
> >> Jason 
> > 
> > 
> 
> 
> 


-- 
Christian Balzer        Network/Systems Engineer                
chibi@xxxxxxx   	Global OnLine Japan/Rakuten Communications
http://www.gol.com/
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