Jeff Koch wrote:
We're setting up a new mailserver with a Gigabyte i-ram drive to handle
the qmail queue, and qmail logs. The i-ram drive uses standard DDR
modules, has a battery backup and is lightning fast - much faster than
solid state drives. We'll use SATA RAID for the maildirs and remainder
of the server.
I'd like to get some input on the best filesystem for the i-ram drive.
EXT3 is out because writes are slowed to the speed of a hard drive. I'm
leaning towards reiserfs or xfs. However, I've read (wikipedia) that
reiserfs is easily corrupted. xfs seems the best.
You mean using ext3 on the i-ram gets you the speed of a hard drive? try
running ext3 with data=journal (full journal mode) and with noatime.
xfs may have the best performance but its data integrity is the worst of
all the filesystems available for Linux besides being one of the
buggiest. It is the filesystem with the largest codebase there is and it
is a filesystem that was ported to Linux with lots of workarounds to
work with the Linux kernel. xfs only journals metadata so you will have
an intact filesystem but you will get @@@@ in files after a crash or
after power loss. No, the i-ram will not make a difference for xfs will
use main memory for data caching. Data will not get a chance to hit the
i-ram in the event of a crash or a power cut.
reiserfs assumes perfect media which is why it is easily corrupted. The
i-ram will probably not give you that problem and besides, this is the
qmail queue you are talking about. It probably will not store that much
mail at all. I am amazed that you feel comfortable with just 1GB. I
would have thought that maybe using the i-ram as an external journal for
an ext3 filesystem on SATA disks in full journal mode would have been
You can also give jfs a shot. It is robust and comes second in most
filesystem tests whether they are reads, writes or writing time at least
according to Bruce Guenter's maildir suitability benchmark. (google fsbench)