[lustre-discuss] Monitoring Lustre IOPS on OSTs

[Andreas Dilger]

Yes, each RPC will increment these stats counters by one. Traditional "IOPS" are measured with 4KB read or write, but in this case the IO sizes are variable.

Also, the client may aggregate multiple disjoint writes into a single RPC. This can be seen in the osd-ldiskfs.*.brw_stats as "discontiguous pages" so this might be considered multiple "IOs" in a single RPC.

Cheers, Andreas

On Jan 23, 2023, at 09:31, Passerini Marco <marco.passerini at cscs.ch> wrote:

I'd like to monitor the IOPS on the Lustre OSTs.


I have stats like this:


[root at xxx04 ~]# lctl get_param obdfilter.xxx-OST0000.stats
obdfilter.xxx-OST0000.stats=
snapshot_time             348287.096066602 secs.nsecs
start_time                0.000000000 secs.nsecs
elapsed_time              348287.096066602 secs.nsecs
read_bytes                3075 samples [bytes] 0 1134592 2891776 2568826650624
write_bytes               1312266 samples [bytes] 1 4194304 5424381521966 4303559271585613940
read                      3075 samples [usecs] 0 489 31040 3417458
write                     1312266 samples [usecs] 1 1630262 6193336309 3686004830368845
setattr                   20373 samples [usecs] 1 61 133314 1090612
punch                     4600 samples [usecs] 3 65 51155 732959
sync                      4 samples [usecs] 443 997 2853 2250847
destroy                   30777 samples [usecs] 11 42634 20978596 33571893182
create                    993 samples [usecs] 1 29995 534579 1518818913
statfs                    135519 samples [usecs] 0 24 610182 4231650
get_info                  108 samples [usecs] 1 3092 6218 17971060
set_info                  10047 samples [usecs] 1 22 83418 770166

From the docs https://wiki.lustre.org/Lustre_Monitoring_and_Statistics_Guide I see:

"""
For read_bytes and write_bytes:

    First number = number of times (samples) the OST has handled a read or write.

"""


I guess this can be considered as OST IOPS?


Regards,

Marco Passerini

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