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 go over the replication network are also slowed down, which results in the network latencies as displayed in our VM level performance charts (green chart in Performance tab in the VirtuCache GUI) showing as high. So this problem might be a CEPH issue and not a network issue.