Re: Filesystem for Linux production database server?

> Linux file systems usually do not support direct I/O (bypassing the buffer
> cache), which means that you're going to have double caching with almost

This is no longer the case. Look at the O_DIRECT open option, which can be used with oracle. Make sure that your distribution has support for it.

> everything except raw devices. You can have up to 256 raw devices on a Linux
> box and if your database is small enough (32-bit system, 2G limit applies),
> that will definitely be the fastest option. My recommendation is to go with
> IBM JFS because it is a battle tested, mature, well performing file system. I
> would advise against XFS because nobody uses it.

Quite a few people use XFS. Its made it both into the -ac branch and into the 2.5 kernel. However, *I* would strongly recommend ext3 as many people run oracle on it and that OS/filesystem combination has been beaten to hell a lot more than linux/JFS. Also, when placed into data=writeback,noatime mode[1] performs *much* better than the default data=ordered. I recall a rerun of that benchmark in which ext3/writeback was pretty close to ext2's performance save that it has much faster recovery on boot.

Second on the "most used" list is reiserfs, however ext3/writeback's direct/block io should be somewhat faster than it.

Being that i don't have my own large-scale personal testing in a publishable form, i'll point you to someone else's work (he, unfortunately, doesn't appear to have had a raid array to beat up with via an SMP server)

http://oregonstate.edu/~kveton/fs/page2.php

I'll note that on my desktop running 2.5.70 the performance for bonnie resulted in the following order (all noatime)

FASTEST: ext3/writeback ; XFS ; JFS ; SLOWEST

but with only a single platter and one cpu, not much can be said :)

Before you get concerned about what writeback means, read the man page for the filesystem you'll find that it is basically what most other filesystems (jfs, xfs, reiserfs, vxfs, etc) use for their default/performance options. however,do make sure that you're patched up to date if you go near data=journal.

[1] The noatime mount parameter should be used for any filesystem

        backing oracle (ext[23],xfs,jfs,reiserfs, etc as there is
        no need to keep updating last access times, so you can
        save a whole pile of ~1k writes.

One other thing: if you are using fibre attached storage and are *not* using async io, then put some usefully large value into /proc/sys/vm/max-readahead, remember it is power of 2 minus one, so youd want to look at values like 255, 511, and 1023.

> As for availability, you'll have to go with some RAID controller and standby
> database or RAC. In case of RAC, your choice of file systems is clear (OCFS).
> Whatever you do, do not configure your RAID as RAID-5 but RAID 1+0 (BARF).

what he said, save that i like raid10.  

> which means that
> On 2003.06.29 11:44, zhu chao wrote:
> > Hi, friends that run oracle on linux:
> > We are running some database on linux, some with UPS protection and some
> > not, all using ext2. Currently we have a DW server running oracle 817/Redhat
> > 7.2/Ext2. When server crash because of power supply, fsck took rather long
> > time!
> > And we are planning migrate to redhat as2.1/9.2, and I am thinking of
> > what kind of filesystem shall I choose for the new server. The database is
> > about 150G.I had planned to use ext3 for it is journal filesystem, But
> > according to http://www.linuxjournal.com/article.php?sid=5841, ext3 is bad
> > for performance, and some friend said he hit filesystem crash with ext3.
> > So,what is your experience using filesystem for oracle in linux?
> > Performance and avaliability is of most important.
> > Thanks.
> >
> >
> > Regards
> > zhu chao
> > msn:[EMAIL PROTECTED]
> > www.cnoug.org
> >
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > --
> > Author: zhu chao
> > INET: [EMAIL PROTECTED]
> >
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