On Sat, 27 Feb 2010, Justin Piszcz wrote:
On Sat, 27 Feb 2010, Justin Piszcz wrote:
>
>
> On Sat, 27 Feb 2010, Justin Piszcz wrote:
>
> >
> >
> > On Fri, 26 Feb 2010, Eric Sandeen wrote:
> >
Hi,
I have found the same results on 2 different systems:
It seems to peak at ~350MiB/s performance on mdadm raid, whether
a RAID-5 or RAID-0 (two separate machines):
The only option I found that allows it to go from:
10737418240 bytes (11 GB) copied, 48.7335 s, 220 MB/s
to
10737418240 bytes (11 GB) copied, 30.5425 s, 352 MB/s
Is the -o nodelalloc option.
How come it is not breaking the 350MiB/s barrier is the question?
Justin.
Besides large sequential I/O, ext4 seems to be MUCH faster than XFS when
working with many small files.
EXT4
p63:/r1# sync; /usr/bin/time bash -c 'tar xf linux-2.6.33.tar; sync'
0.18user 2.43system 0:02.86elapsed 91%CPU (0avgtext+0avgdata 5216maxresident)k
0inputs+0outputs (0major+971minor)pagefaults 0swaps
linux-2.6.33 linux-2.6.33.tar
p63:/r1# sync; /usr/bin/time bash -c 'rm -rf linux-2.6.33; sync'
0.02user 0.98system 0:01.03elapsed 97%CPU (0avgtext+0avgdata 5216maxresident)k
0inputs+0outputs (0major+865minor)pagefaults 0swaps
XFS
p63:/r1# sync; /usr/bin/time bash -c 'tar xf linux-2.6.33.tar; sync'
0.20user 2.62system 1:03.90elapsed 4%CPU (0avgtext+0avgdata 5200maxresident)k
0inputs+0outputs (0major+970minor)pagefaults 0swaps
p63:/r1# sync; /usr/bin/time bash -c 'rm -rf linux-2.6.33; sync'
0.03user 2.02system 0:29.04elapsed 7%CPU (0avgtext+0avgdata 5200maxresident)k
0inputs+0outputs (0major+864minor)pagefaults 0swaps
So I guess that's the tradeoff, for massive I/O you should use XFS, else,
use EXT4?
I still would like to know however, why 350MiB/s seems to be the maximum
performance I can get from two different md raids (that easily do 600MiB/s
with XFS).
Is this a performance issue within ext4 and md-raid?
The problem does not exist with xfs and md-raid.
Justin.
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