We have 4GB's of RAM on the I-RAM which should be more than enough for the qmail queue and log files. I'll check out JFS. Thanks

At 06:49 PM 12/21/2007, you wrote:
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 better.

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)

Best Regards,

Jeff Koch, Intersessions


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