[Gluster-devel] Fw: Re: Corvid gluster testing

[Vijay Bellur]

On 08/06/2014 12:11 AM, David F. Robinson wrote:
> I have been testing some of the fixes that Pranith incorporated into the
> 3.5.2-beta to see how they performed for moderate levels of i/o. All of
> the stability issues that I had seen in previous versions seem to have
> been fixed in 3.5.2; however, there still seem to be some significant
> performance issues.  Pranith suggested that I send this to the
> gluster-devel email list, so here goes:
> I am running an MPI job that saves a restart file to the gluster file
> system.  When I use the following in my fstab to mount the gluster
> volume, the i/o time for the 2.5GB file is roughly 45-seconds.
> /    gfsib01a.corvidtec.com:/homegfs /homegfs glusterfs
> transport=tcp,_netdev 0 0
> /
> When I switch this to use the NFS protocol (see below), the i/o time is
> 2.5-seconds.
> /  gfsib01a.corvidtec.com:/homegfs /homegfs nfs
> vers=3,intr,bg,rsize=32768,wsize=32768 0 0/
> The read-times for gluster are 10-20% faster than NFS, but the write
> times are almost 20x slower.

What is the block size of the writes that are being performed? You can 
expect better throughput and lower latency with block sizes that are 
close to or greater than 128KB.

-Vijay