23 Apr
2020
23 Apr
'20
3:39 p.m.
Hi,
Am 23.04.20 um 14:06 schrieb Igor Fedotov:
I don't recall any additional tuning to be applied
to new DB volume. And
assume the hardware is pretty the same...
Do you still have any significant amount of data spilled over for these
updated OSDs? If not I don't have any valid explanation for the phenomena.
just the 64k from here:
https://tracker.ceph.com/issues/44509
You might want to try "ceph osd bench" to
compare OSDs under pretty the
same load. Any difference observed
Servers are the same HW. OSD Bench is:
# ceph tell osd.0 bench
{
"bytes_written": 1073741824,
"blocksize": 4194304,
"elapsed_sec": 16.091414781000001,
"bytes_per_sec": 66727620.822242722,
"iops": 15.909104543266945
}
# ceph tell osd.36 bench
{
"bytes_written": 1073741824,
"blocksize": 4194304,
"elapsed_sec": 10.023828538,
"bytes_per_sec": 107118933.6419194,
"iops": 25.539143953780986
}
OSD 0 is a Toshiba MG07SCA12TA SAS 12G
OSD 36 is a Seagate ST12000NM0008-2H SATA 6G
SSDs are all the same like the rest of the HW. But both drives should
give the same performance from their specs. The only other difference is
that OSD 36 was directly created with the block.db device (Nautilus
14.2.7) and OSD 0 (14.2.8) does not.
Stefan
>
> On 4/23/2020 8:35 AM, Stefan Priebe - Profihost AG wrote:
>> Hello,
>>
>> is there anything else needed beside running:
>> ceph-bluestore-tool --path /var/lib/ceph/osd/ceph-${OSD}
>> bluefs-bdev-new-db --dev-target /dev/vgroup/lvdb-1
>>
>> I did so some weeks ago and currently i'm seeing that all osds
>> originally deployed with --block-db show 10-20% I/O waits while all
>> those got converted using ceph-bluestore-tool show 80-100% I/O waits.
>>
>> Also is there some tuning available to use more of the SSD? The SSD
>> (block-db) is only saturated at 0-2%.
>>
>> Greets,
>> Stefan
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