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Hi Christian,
I’ll give you a much better dump of detail :)
Running RHEL 7.1,
ceph version 0.94.5
all ceph disks are xfs, with journals on a partition on the disk
Disks: 6Tb spinners.
Erasure coded pool with 4+1 EC ISA-L also.
No scrubbing reported in the ceph log, the cluster isn’t old enough yet to be doing any deep scrubbing.
Also the cpu usage of the osd deamon that controls the disk isn’t spiking which I have seen previously when scrubbing or deep scrubbing is taking place.
All disks are at 2% utilisation as given by df.
For explicitness:
[root@au-sydney ~]# ceph -s
cluster ff900f17-7eec-4fe1-8f31-657d44b86a22
health HEALTH_OK
monmap e5: 5 mons at {au-adelaide=10.50.21.24:6789/0,au-brisbane=10.50.21.22:6789/0,au-canberra=10.50.21.23:6789/0,au-melbourne=10.50.21.21:6789/0,au-sydney=10.50.21.20:6789/0}
election epoch 274, quorum 0,1,2,3,4 au-sydney,au-melbourne,au-brisbane,au-canberra,au-adelaide
osdmap e8549: 120 osds: 120 up, 120 in
pgmap v408422: 8192 pgs, 2 pools, 7794 GB data, 5647 kobjects
9891 GB used, 644 TB / 654 TB avail
8192 active+clean
client io 68363 kB/s wr, 1249 op/s
Cheers,
Bryn
On 30 Nov 2015, at 12:57, Christian Balzer < chibi@xxxxxxx> wrote:
Hello,
On
Mon, 30 Nov 2015 07:15:35 +0000 MATHIAS, Bryn (Bryn) wrote:
Hi All,
I am seeing an issue with ceph performance.
Starting from an empty cluster of 5 nodes, ~600Tb of storage.
It
would be helpful to have more details (all details in fact) than this.
Complete
HW, OS, FS used, Ceph versions and configuration details (journals
on
HDD, replication levels etc).
While
this might not seem significant to your current question, it might
prove
valuable as to why you're seeing performance problems and how to
address
them.
monitoring disk usage in nmon I see rolling 100% usage of a disk.
Ceph -w doesn’t report any spikes in throughput and the application
putting data is not spiking in the load generated.
The
ceph.log should give a more detailed account, but assuming your client
side
is indeed steady state, this could be very well explained by
scrubbing,
especially deep-scrubbing.
That
should also be visible in the ceph.log.
Christian
│sdg2 0% 0.0 537.5|
|
│ │sdh 2% 4.0
4439.8|RW
│
│sdh1 2% 4.0
3972.3|RW
│
│sdh2 0% 0.0 467.6|
|
│ │sdj 3% 2.0
3524.7|RW
│
│sdj1 3% 2.0
3488.7|RW
│
│sdj2 0% 0.0 36.0|
|
│ │sdk 99% 1144.9
3564.6|RRRRRRRRRRRRRWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW>
│
│sdk1 99% 1144.9
3254.9|RRRRRRRRRRRRRWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWWW>
│ │sdk2 0% 0.0 309.7|W
|
│ │sdl 1% 4.0 955.1|R
|
│ │sdl1 1% 4.0 791.3|R
|
│
│sdl2 0% 0.0 163.8|
|
Is this anything to do with the way objects are stored on the file
system? I remember reading that as the number of objects grow the files
on disk are re-orginised?
This issue for obvious reasons causes a large degradation in
performance, is there a way of mitigating it? Will this go away as my
cluster reaches a higher level of disk utilisation?
Kind Regards,
Bryn Mathias
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--
Christian
Balzer Network/Systems Engineer
chibi@xxxxxxx
Global
OnLine Japan/Fusion Communications
http://www.gol.com/
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