I use the following method, and haven't ever noticed it being interfered
with:
* set osd_mclock_skip_benchmark to true
* remove any iops values that may have been added
* run fio benchmarks on each model of disk
* run a script that, for each osd, interrogates the drive model of the
block device using smartctl and sets the iops value from my benchmark
Running with the mclock profile set to balanced works really well for us
(on squid 19.2.1, which performs better for us than reef did).
Chris
On 31/03/2025 09:07, Michel Jouvin wrote:
Hi,
Looking at our configuration during a recovery operation (misplaced
objects after adding PG in a pool) that I found a bit slow, I saw that
~30 OSD over 500 had an entry for osd_mclock_max_capacity_iops_hdd in
the configuration DB (and almost all the SSD). Despite all HDD and SSD
being the same models (and the server HW being the same). As this
value can have a significant impact on recovery time/speed with
mclock, I was wondering if this value is periodically refreshed, in
case one measurement was wrong (perturbated by external factors). The
documentation is not very clear about this and seems to say that the
bench used to estimate the IOPS capacity is run only when the OSD is
activated (which may make sense as it is before there is any other
activity on it)? I'm also wondering why we observe value like 350 on
some OSD as the HW is the same on all servers?
Currently, I tend to remove all the osd_mclock_max_capacity_iops_xxx
entries from the DB periodically but it's probably not the right
approach...
Cheers,
Michel
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