[Gluster-users] performance - what can I expect

[Pascal Suter]

Hi all

I am currently testing gluster on a single server. I have three bricks, 
each a hardware RAID6 volume with thin provisioned LVM that was aligned 
to the RAID and then formatted with xfs.

i've created a distributed volume so that entire files get distributed 
across my three bricks.

first I ran a iozone benchmark across each brick testing the read and 
write perofrmance of a single large file per brick

i then mounted my gluster volume locally and ran another iozone run with 
the same parameters writing a single file. the file went to brick 1 
which, when used driectly, would write with 2.3GB/s and read with 
1.5GB/s. however, through gluster i got only 800MB/s read and 750MB/s 
write throughput

another run with two processes each writing a file, where one file went 
to the first brick and the other file to the second brick (which by 
itself when directly accessed wrote at 2.8GB/s and read at 2.7GB/s) 
resulted in 1.2GB/s of aggregated write and also aggregated read 
throughput.

Is this a normal performance i can expect out of a glusterfs or is it 
worth tuning in order to really get closer to the actual brick 
filesystem performance?

here are the iozone commands i use for writing and reading.. note that i 
am using directIO in order to make sure i don't get fooled by cache :)

./iozone -i 0 -t 1 -F /mnt/brick${b}/thread1 -+n -c -C -e -I -w -+S 0 -s 
$filesize -r $recordsize > iozone-brick${b}-write.txt

./iozone -i 1 -t 1 -F /mnt/brick${b}/thread1 -+n -c -C -e -I -w -+S 0 -s 
$filesize -r $recordsize > iozone-brick${b}-read.txt

cheers

Pascal