Generally bdev-new-db performs no migration, RocksDB might eventually do
that but no guarantee it moves everything.
One should use bluefs-bdev-migrate to do actual migration.
And I think that's the root cause for the above ticket.
Thanks,
Igor
On 4/24/2020 2:37 PM, Stefan Priebe - Profihost AG wrote:
No not a standalone Wal I wanted to ask whether
bdev-new-db migrated
dB and Wal from hdd to ssd.
Stefan
> Am 24.04.2020 um 13:01 schrieb Igor Fedotov <ifedotov(a)suse.de>de>:
>
>
>
> Unless you have 3 different types of disks beyond OSD (e.g. HDD, SSD,
> NVMe) standalone WAL makes no sense.
>
>
> On 4/24/2020 1:58 PM, Stefan Priebe - Profihost AG wrote:
>> Is Wal device missing? Do I need to run *bluefs-bdev-new-db and Wal?*
>>
>> Greets,
>> Stefan
>>
>>> Am 24.04.2020 um 11:32 schrieb Stefan Priebe - Profihost AG
>>> <s.priebe(a)profihost.ag>ag>:
>>>
>>> Hi Igor,
>>>
>>> there must be a difference. I purged osd.0 and recreated it.
>>>
>>> Now it gives:
>>> ceph tell osd.0 bench
>>> {
>>> "bytes_written": 1073741824,
>>> "blocksize": 4194304,
>>> "elapsed_sec": 8.1554735639999993,
>>> "bytes_per_sec": 131659040.46819863,
>>> "iops": 31.389961354303033
>>> }
>>>
>>> What's wrong wiht adding a block.db device later?
>>>
>>> Stefan
>>>
>>> Am 23.04.20 um 20:34 schrieb Stefan Priebe - Profihost AG:
>>>> Hi,
>>>> if the OSDs are idle the difference is even more worse:
>>>> # ceph tell osd.0 bench
>>>> {
>>>> "bytes_written": 1073741824,
>>>> "blocksize": 4194304,
>>>> "elapsed_sec": 15.396707875000001,
>>>> "bytes_per_sec": 69738403.346825853,
>>>> "iops": 16.626931034761871
>>>> }
>>>> # ceph tell osd.38 bench
>>>> {
>>>> "bytes_written": 1073741824,
>>>> "blocksize": 4194304,
>>>> "elapsed_sec": 6.8903985170000004,
>>>> "bytes_per_sec": 155831599.77624846,
>>>> "iops": 37.153148597776521
>>>> }
>>>> Stefan
>>>> Am 23.04.20 um 14:39 schrieb Stefan Priebe - Profihost AG:
>>>>> 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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