[Gluster-users] about HA infrastructure for hypervisors

[Brian Candler]

On Wed, Jun 27, 2012 at 05:28:43PM -0500, Nathan Stratton wrote:
> [root at virt01 ~]# dd if=/dev/zero of=foo bs=1M count=5k
> 5120+0 records in
> 5120+0 records out
> 5368709120 bytes (5.4 GB) copied, 26.8408 s, 200 MB/s
> 
> >But doing a dd if=/dev/zero bs=1024k within a VM, whose image was mounted on
> >glusterfs, I was getting only 6-25MB/s.
> 
> [root at test ~]# dd if=/dev/zero of=foo bs=1M count=5k
> 5120+0 records in
> 5120+0 records out
> 5368709120 bytes (5.4 GB) copied, 172.706 s, 31.1 MB/s

That's what I consider unimpressive - slower than a single disk, when you
have an array of 16.  I should try a pair of drbd nodes as a fair comparison
though.

Having said that, multiple clients running concurrently should be able to
use the remaining bandwidth, so the aggregate throughput should be fine.

BTW, there used to be an issue with glusterfs 3.2 in the way it scaled its
thread pool, which limited concurrency:
http://gluster.org/pipermail/gluster-users/2012-February/009590.html
But that has been fixed in 3.3 (commit 2d836326)

Regards,

Brian.