Hi Luis,
I am reading reading some documentation about mClock and have two questions.
First, about the IOPS. Are those IOPS disk IOPS or other kind of IOPS? And
what the assumption of those? (Like block size, sequential or random
reads/writes)?
This is the result of testing running OSD bench random writes at 4 KiB
block size.
But what I get is:
"osd_mclock_scheduler_background_best_effort_lim": "999999",
"osd_mclock_scheduler_background_best_effort_res": "18",
"osd_mclock_scheduler_background_best_effort_wgt": "2",
"osd_mclock_scheduler_background_recovery_lim": "135",
"osd_mclock_scheduler_background_recovery_res": "36",
"osd_mclock_scheduler_background_recovery_wgt": "1",
"osd_mclock_scheduler_client_lim": "90",
"osd_mclock_scheduler_client_res": "36",
"osd_mclock_scheduler_client_wgt": "1",
Which seems very low according to what my disk seems to be able to handle.
Is this calculation the expected one? Or did I miss something on how those
profiles are populated?
The above values are a result of distributing the IOPS across all the OSD
shards as defined by the
osd_op_num_shards_[hdd|ssd] option. For HDDs, this is set to 5 and
therefore the IOPS will be
distributed across the 5 shards (i.e. for e.g., 675/5 for
osd_mclock_scheduler_background_recovery_lim
and so on for other reservation and limit options).
-Sridhar