[Fwd: Re: Show stopper for large disks with 5.4-RELEASE]
security at jim-liesl.org
Wed Jun 8 21:50:11 GMT 2005
Dmitriy Kirhlarov wrote:
>On Wed, 08 Jun 2005, Pierre DAVID wrote:
>>Do you have a clue to help us use FreeBSD and not switch on Linux
>>for this service?
>You can create many small partitions and mount_unionfs.
Actually it's a very valid choice. At this time, Linux offers ext3, XFS
(from SGI), JFS (from IBM) and RieserFS as journaled file systems (as in
no fscking fsck). JFS, XFS and RieserFS offer very good performance
with big directories (like Maildir style mailboxes could create) and
recover from unexpected outages quickly (journal replay to last
checkpoint is typically seconds) and robustly. In fact, if I were to
deploy a large Maildir system, where users could have thousands of files
per directory, I would definitly be looking at JFS, XFS or Rieser.
Linux also has a WORKING logical volume manager, and a WORKING s/w raid5
whose performance is close to all but the most high end RAID
controllers. But I digress.
I really like FreeBSD for a lot of things, but outside of snap and
union, storage and filesystems are pretty much SOTA circa 1998
I'm not that amazed by his numbers. on a 5.3R system, when I use snap
to freeze a dump of a 13% used 140 gb gmirror partition, the system
(2ghz AMD, SATA150 drives) goes out to lunch for about 45 seconds,
hanging all IO's to the partition. Scale that upto 1.8TB, and I could
see where you could be going nowhere for a good 10 minutes just waiting
for the snap to finish. Still better than waiting hours for fsck, but
nowhere near the recovery speed of a true journaled system.
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