Re: EXT4 is ~2X as slow as XFS (593MB/s vs 304MB/s) for writes?

[Justin Piszcz]

On Fri, 26 Feb 2010, Eric Sandeen wrote:

> Justin Piszcz wrote:
> > Hello,
> >
> > Is it possible to 'optimize' ext4 so it is as fast as XFS for writes?
> > I see about half the performance as XFS for sequential writes.
> >
> > I have checked the doc and tried several options, a few of which are shown
> > below (I have also tried the commit/journal_async/etc options but none
> > of them get the write speeds anywhere near XFS)?
> >
> > Sure 'dd' is not a real benchmark, etc, etc, but with 10Gbps between 2
> > hosts I get 550MiB/s+ on reads from EXT4 but only 100-200MiB/s write.
> >
> > When it was XFS I used to get 400-600MiB/s for writes for the same RAID
> > volume.
> >
> > How do I 'speed' up ext4?  Is it possible?
>
> Aside from Dmitry's suggestion to time sync as well (although for 10G, you are
> likely not leaving much in cache) I'd ask:
>
> What kernel version?  what xfsprogs/e2fsprogs version?
2.6.33/x86_64

ii  xfsprogs                                3.1.1                    Utilities for managing the XFS filesystem
ii  e2fsprogs                               1.41.10-1                ext2/ext3/ext4 file system utilities

> Were the filesystems created to align with raid geometry?
Only default options were used except the mount options.  If that is the
culprit, I have some more testing to do, thanks, will look into it.

> mkfs.xfs has done that forever; mkfs.ext4 only will do so (automatically)
> with recent kernel+e2fsprogs.
How recent?


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