On Thu, Nov 18, 1999 at 07:36:17PM -0800, Michael Boyiazis mentioned:
> Greetings,
> We are thinking of using OpenDiskSuite to
> mirror a disk which contains /var/qmail so that
> if the disk dies we have (hopefully) not lost the
> mail in the queue. Will this work?
It'll work fine. Seeing as you are considering OpenDiskSuite, I'll assume
you're using it on Solaris/Sparc/SCSI.
Straight mirroring with disksuite is a bit faster than on Veritias - I
could only recommend Veritas if you had a large number, or huge
filesystems - it's very complex. To just ensure that you reduce the
possibility of losing your mail, disksuite is fine. If you don't have that
many users, and performance isn't really an issue, a straight mirror should
be OK. If you are looking at requiring more than 2MB/sec off the disk,
consider getting a multipack, and at least six disks...and striping the
mirrors - this will almost treble your read performance, and nearly double
reading, over a simple mirror.
With a standard mirror, you almost double read performance, and half
write performance (disksuite will "roundrobin" reads, doubling bandwidth,
but have to write to two disks, halving write bandwidth) - not nice on a
mail queue, where you get about 50% reads/50% writes. Seeing as this isn't
really qmail related, mail me off-list, if you have any more specific
questions..
> Would I then need to run the queue through the
> queue recovery script or should it be okay without?
It should be fine. Mirroring is there to ensure the application doesn't
see any problem with the physical disks whatsoever.
Needless to say, mirroring still doesn't protect against ...
"# rm -r /var/ tmp/directory"
.. mistakes :)
Kate
--
Microsoft. The best reason in the world to drink beer.
http://www.redbrick.dcu.ie/~valen
