CEPH

11 Jul: Multi Pathing in RedHat and SuSE CEPH

There are two major commercial CEPH distributions, RedHat and SuSE. As of July 2019, both differ in how their Multi Pathing works when connected to VMware. SuSE supports active-active iSCSI gateway deployment. So in vCenter all paths to SuSE Enterprise Storage (SES) CEPH show as ‘active (IO)’. So in the…

05 Jun: High network latencies in CEPH as shown in VirtuCache charts

If CEPH is slow, it might show up as high network latencies in VirtuCache when VirtuCache is configured in ‘Write-Back 1 Replica’ mode. This is because, as CEPH slows down, VirtuCache throttles down the rate at which writes are committed to CEPH. As writes are throttled down, write replicas that…