Re: Opinions XFS
On Sat, 4 Aug 2007, michael@estone.ca wrote:
Quoting Sergio Belkin <sebelk@gmail.com>:
Hi I was reading http://oss.sgi.com/projects/xfs/index.html and was
amazed because XFS powerful features. But I'd like opinions if xfs
should be a good alternative to ext3 in typical cases, or if it should
be relegated to critical missions servers.
XFS is a rock solid filesystem. So is EXT3. XFS generally will be faster
than EXT3, but only for medium to large files. EXT3 is faster with
really small files around 1K or so. Depending on your needs, you may
want to benchmark the 2 filesystems to compare. Bonnie++ is a nice tool
to use, as it lets you change the test file sizes around.
XFS and grub do not work nicely together, therefore you'll need /boot
mounted with EXT3, everything else can be XFS, even / .
XFS can destroy files, but its more of myth when people say it will just
magically destroy files. XFS is designed this way as its a meta-data
only journalling filesystem. Bottom line, is that only recently written
files, within 60 seconds of write, will get hosed if your system
suddenly loses power. Therefore, if you use XFS, use a UPS, of which
will auto halt your box in case of power loss. Use good hardware, and of
course, have good backups. Also, use smartmontools to monitor your
drives. Its not 100% perfect against failing drives, but its better than
nothing.
I suspect many of the bad experiences with XFS were using IDE drives on
32-bit x86 hardware. XFS was originally developed on RISC hardware, and
did not fit well with register-starved hardware. Red Hat in particular
has worked hard to run with 4k stacks, and XFS users have had to build
kernels with larger stack size. The xfsrepair tool needed ample
resources, so if you had a problem with XFS on a typical system (PIII with
256M) you had to move the disk to a better box to sort things out.
I would not recommend XFS for a workstation environment where its your system
drive. Why? Only because you might have to hard reboot it every once in
awhile. Perhaps for storing media type files on a seperate [sic]
filesystem though.
I use SGI IRIX workstations for remote sensing. The filesystems are all
XFS. Over the years I've had lots of disks fail, and also several SCSI
controllers. Often the first sign of hardware problems is errors from
fsr. Since the system disks were the oldest, most of the workstations
have crashed when the the root filesystem went poof, but the other (data)
filesystems were recovered with minimal problems.
I did have the experience of working on a program only to have big chunks
of an XFS filesystem on a RAID (5 9G SCSI disks) go poof when the
controller for the external SCSI failed. I moved the RAID to another box
and what was left of the XFS filesystem was fine.
I'm quite impressed with the stability and performance of XFS and having been
using it for over a year on production servers that run mail, file and web
serving. (x86_64 etch)
Let us know how you feel once you have experienced a few hardware
failures.
--
George N. White III <aa056@chebucto.ns.ca>
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