[PVE-User] iowait problems with gluster drive - is bcache the answer?

Lindsay Mathieson lindsay.mathieson at gmail.com
Mon Nov 3 06:00:44 CET 2014

I have gluster replica setup with 2 nodes, one disk per node.
Sustained writes are good enough - 80MB/s, reads are 140/MB/s

But once I start 4+ windows VM's on it I have problems with iowait
sitting at 10%, peaking at 20%, this produces noticable pauses in the
VM's (VDI usage).

Its interesting because the nas, which only had a transfer rate of
30MB/s didn't have this problem, I presume because it was running in

If I add a SSD cache using bcache, would this help reduce iowait?

I'm using pve kernel 3.10-5, which I presume has bcache integrated, as
in the mainline kernel.



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