[Gluster-users] Reading not distributed across bricks

Ray Mannings manningsray1 at gmail.com
Thu Aug 7 21:36:41 UTC 2014


I have a small (5 node) compute cluster running an MPI job that needs to
read from a few 20 GB files. These files are stored in a gluster volume
composed of bricks from four storage nodes. I originally made the volume
with a replica count of 2, but in an attempt to improve read performance, I
recreated it with a replica count of 4.

However, reading turned out to be even slower! I checked out disk access
with iotop, and for one file, only two of the bricks are being read from.
For another file, only _one_ brick is accessed! Volume top read also shows
the same thing.

What might be the problem? There are 40 threads across the cluster trying
to read at the same time; shouldn't this be automatically load balanced
across each brick?

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