Hi Luis, > We are testing migrations from a cluster running Pacific to Reef. In > pacific we needed to tweak osd_mclock_max_capacity_iops_hdd to have decent > performances of ou cluster. > It would be helpful to know the procedure you are employing for the migration. > > But in reef it looks like changing the value of > osd_mclock_max_capacity_iops_hdd does not impact cluster performances. Did > osd_mclock_max_capacity_iops_hdd became useless? > "osd_mclock_max_capacity_iops_hdd" is still valid in Reef as long as it accurately represents the capability of the underlying OSD device for the intended workload. Between Pacific and Reef many improvements to the mClock feature have been made. An important change relates to the automatic determination of cost per I/O which is now tied to the sequential and random IOPS capability of the underlying device of an OSD. As long as "osd_mclock_max_capacity_iops_hdd" and "osd_mclock_max_sequential_bandwidth_hdd" represent a fairly accurate capability of the backing OSD device, the performance should be along expected lines. Changing the "osd_mclock_max_capacity_iops_hdd" to a value that is beyond the capability of the device will obviously not yield any improvement. If the above parameters are representative of the capability of the backing OSD device and you still see lower than expected performance, then it could be some other issue that needs looking into. -Sridhar _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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