Hi Frédéric,

Thank you the ideas.

Cluster is half updated but on the osds which updated are:

"osd_op_queue": "mclock_scheduler",
"osd_op_queue_cut_off": "high",

I'd say the value when I do the benchmark how ceph calculates it, it is too 
high. We have 4 osd on 1 nvme and it sets the value on the last osd from the 4 
on nvme which is the highest:
36490.280637

However I changed this value already on some other fully upgraded cluster 
divided by 4 and didn't help.
Buffered io turned on since octopus, didn't change it.

For a quick check that specific osd seems like what you tell:

1 : device size 0x6fc7c00000 : own 
0x[40000~4e00000,12f70000~2252d0000,23b060000~21a230000,4583e0000~20f890000,6b1630000~200000000,35a78f0000~478a20000]
 = 0xccc5b0000 : using 0xa60ed0000(42 GiB) : bluestore has 0x62e79f0000(396 
GiB) available
wal_total:0, db_total:456087987814, slow_total:0


Istvan



________________________________
From: Frédéric Nass <frederic.n...@univ-lorraine.fr>
Sent: Monday, November 4, 2024 4:14 PM
To: Szabo, Istvan (Agoda) <istvan.sz...@agoda.com>
Cc: Tyler Stachecki <stachecki.ty...@gmail.com>; Ceph Users <ceph-users@ceph.io>
Subject: Re: [ceph-users] Re: Slow ops during index pool recovery causes 
cluster performance drop to 1%

Email received from the internet. If in doubt, don't click any link nor open 
any attachment !
________________________________

Hi Istvan,

Is you upgraded cluster using wpq or mclock scheduler? (ceph tell osd.X config 
show | grep osd_op_queue)

Maybe your OSDs set their osd_mclock_max_capacity_iops_* capacity too low on 
start (ceph config dump | grep osd_mclock_max_capacity_iops) limiting their 
performance.

You might want to raise these figures if set or go back to wpq to give you 
enough time to understand how mclock works.

Also, check bluefs_buffered_io as it's default value changed over time. Better 
run 'true' now (ceph tell osd.X config show | grep bluefs_buffered_io)
Also, check for any overspilling as there's been a bug in the past with 
overspilling not being reported on ceph status (ceph tell osd.X bluefs stats, 
SLOW line should show 0 Bytes and 0 FILES).

Regards,
Frédéric.

----- Le 4 Nov 24, à 5:24, Istvan Szabo, Agoda istvan.sz...@agoda.com a écrit :

> Hi Tyler,
>
> To be honest we don't have anything set by ourselves regarding compaction and
> rocksdb:
> When I check the socket with ceph daemon on nvme and on ssd both have default
> false on compactL
> "mon_compact_on_start": "false"
> "osd_compact_on_start": "false",
>
> Rocksdb also default:
> bluestore_rocksdb_options":
> "compression=kNoCompression,max_write_buffer_number=4,min_write_buffer_number_to_merge=1,recycle_log_file_num=4,write_buffer_size=268435456,writable_file_max_buffer_size=0,compaction_readahead_size=2097152,max_background_compactions=2,max_total_wal_size=1073741824"
>
> This is 1 event during the slow ops out of the 20:
> https://gist.githubusercontent.com/Badb0yBadb0y/30de736f5d2bd6ec48aa7acf0a3caa14/raw/1070acbf82cc8d69efc04e4e0583e7f83bd33b3f/gistfile1.txt
>
> All belongs to a bucket which doing streaming operation which means continuous
> delete and upload 24/7.
>
> I can see throttled options but still don't understand why the high latency.
>
>
> ty
>
> ________________________________
> From: Tyler Stachecki <stachecki.ty...@gmail.com>
> Sent: Sunday, November 3, 2024 4:07 PM
> To: Szabo, Istvan (Agoda) <istvan.sz...@agoda.com>
> Cc: Ceph Users <ceph-users@ceph.io>
> Subject: Re: [ceph-users] Re: Slow ops during index pool recovery causes 
> cluster
> performance drop to 1%
>
> Email received from the internet. If in doubt, don't click any link nor open 
> any
> attachment !
> ________________________________
>
> On Sun, Nov 3, 2024 at 1:28 AM Szabo, Istvan (Agoda)
> <istvan.sz...@agoda.com> wrote:
>> Hi,
>>
>> I'm updating from octopus to quincy and all in our cluster when index pool
>> recovery kicks off, cluster operation drops to 1%, slow ops comes non-stop.
>> The recovery takes 1-2 hours/nodes.
>>
>> What I can see the iowait on the nvme drives which belongs to the index pool 
>> is
>> pretty high, however the throughput is less than 500MB/s, the iops is less 
>> than
>> 5000/sec.
> ...
>> after update and machine reboot compaction kicks off which generates 30-40
>> iowait on the node, we prevent with "noup" flag to put these osds into the
>> cluster until compaction finished, however when we have 0 iowait after
>> compaction, I unset noup so recovery can start which causes the above issue. 
>> If
>> I wouldn't set noup it would cause even bigger issue.
>
> By any chance, are you specifying a value for
> bluestore_rocksdb_options in your ceph.conf? The compaction
> observation at reboot in particular is odd.
>
> Tyler
>
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