[PLUG] XFS experiences

[Eli Stair]

I'll give a brief brief, if you want more info I'll be happy to
provide details ;)

XFS is great.  However, so is ext3.  (very non-commital ;)

In the event that everything works OK, I've been extremely happy with
XFS.  When I've had failures they are tremendously huge, and sometimes
have a creeping-doom leaving up to them making recovery painful.  I
used to rant about how inferior ext3 was, and scoff at those to didn't
take the time to test and tweek _every_ filesystem tunable and
generate pretty graphs documenting superiority... I'm recovering from
that now!

After unaddressed significant XFS bugs lingering through numerous
in-kernel releases and XFS project releases, I realized it wasn't
something that I wanted to be running on critical systems.  I've had
issues with kernel bugs on ext3, but they've been addressed _swiftly_
by Redhat and the developers.  XFS had numerous bugzilla entries from
me for a long time, that never responded...

Pros:

XFS:
  Fast.  Tunable.  Chic.

ext3:
  Fast.
  Extremely well-tested and proven recovery/lint tools.
  Great full-time coder/vendor support.

Cons:

XFS:
  If it breaks, plan on recovering from backup and switching to a
different filesystem.  If it's a repeatable bug, you'll hit it
again... and again... and post how repeatable it is... and get no
response.

ext3:
  The docs are only like 10% as big ;)
  Far fewer filesystem layout options.

Breakdown:
  ext3 is fast when set up right, and very stable.  If you've got the
new hardware investment, there are a number of things you can do to
tweak your layout properly for your workload.   If you'd like to chat
about it, let me know.  If you want to play with a system specifically
for non-critical temporary data with massively concurrent IO (and you
have a LOT of money to make that work), go with XFS (or just buy some
Spinnakers).  If you want a really capable, stable, and warm-fuzzy
system that is capable of massively concurrent IO (within the limits
of your hardware), I'd go with ext3 (or just buy some Spinnakers)  and
put a bit of effort (a couple days) into planning and testing it.

IMO.

Cheers,

/eli




On 4/20/06, Roderick A. Anderson <raanders at acm.org> wrote:
> Ref: SCSI vs. SATA RAID messages.
>
> I'm down to the point of ordering our new ( specialized ) server so I'm
> thinking of other performance considerations for the software it will be
> running.  This brings up file systems.
>     I typically just choose ext3 and SWAG a partition scheme depending
> on how much disk space the system has.  This has worked for well for the
> general purpose systems I've build to date.  Since the software we'll be
> running is very disk and RAM intensive we've loaded up ( given the
> projected work load ) on RAM and the SCSI RAID will help but I'm now
> looking at file systems.
>     Choices fall as either ext3 and XFS.  I know how ext3 works and it's
> warts but I've never used XFS.  The reason I'm not considering ReiserFS
>   is we have million's of files ranging in size from a few KByte to a
> few GByte in size.
>     There are also a lot of temporary files that are short lived so --
> according to the XFS articles I've read -- will never hit the disks.
>
> What are your thoughts and ideas on XFS as a file system.
>
>
> TIA,
> Rod
> --
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