[Gluster-users] Performance

[Jan Písačka]

On 27.4.2011 01:31, Joe Landman wrote:
> ...  Also, understand that ext* suffers badly under intense parallel
> loads.  Keep that in mind as you make your file system choice.

What sort of suffering can I expect? Is it relevant to high performance
RAID[56] systems only or also for a single hard drive test cases? I made
a quick local writing test with fio and a 1TB SATA disk and could not
see any problem. The configuration was identical for both ext4 and xfs
filesystems:

Ext4 filesystem:

[ext4w]
rw=write
size=4g
directory=/mnt/export
iodepth=16
direct=0
blocksize=512k
numjobs=8
ioengine=vsync
create_on_open=1

  WRITE: io=32708MB, aggrb=100023KB/s, minb=102424KB/s, maxb=102424KB/s,
mint=334850msec, maxt=334850msec

Disk stats (read/write):
  sdb: ios=11/63707, merge=0/7971550, ticks=2347/46130116,
in_queue=46203840, util=99.82%


XFS filesystem:

[xfsw]
.
.
all the same
.


  WRITE: io=32708MB, aggrb=88095KB/s, minb=90209KB/s, maxb=90209KB/s,
mint=380191msec, maxt=380191msec

Disk stats (read/write):
  sdb: ios=12/71594, merge=0/2191, ticks=2326/54558130,
in_queue=54641400, util=99.92%


With on-disk write-caching =  0 (off):

ext4:
  WRITE: io=32708MB, aggrb=34179KB/s, minb=35000KB/s, maxb=35000KB/s,
mint=979907msec, maxt=979907msec

Disk stats (read/write):
  sdb: ios=20/164893, merge=0/16622549, ticks=1953/64535056,
in_queue=64536990, util=97.41%

xfs:
  WRITE: io=32708MB, aggrb=42452KB/s, minb=43471KB/s, maxb=43471KB/s,
mint=788954msec, maxt=788954msec

Disk stats (read/write):
  sdb: ios=4/71372, merge=0/2292, ticks=1236/114143050,
in_queue=114306843, util=99.89%



Is the load sufficient? The system has 8GB of memory. Thanks for any
response.

Jan