On Tue, Jul 13, 2004 at 01:38:31PM +0100, Paul Jakma mentioned:
> Ouch. RAID1+0 on four disks, so you get capacity and speed of
> two-disk RAID0 but reliability of four disks where you can only
> tolerate one failure? You'd be better off with RAID5 on three disks +
> hot spare - sameish read performance, same capacity, but you can
> tolerate two failures (provided second failure doesnt occur before
> hot spare has synced).
No, if you raid 1 before you raid 0, you can lose half you disks, and
keep going (though they have to be the right half!). It's the
configuration Sun recommend in all installations to people that have loads
of money; RAID1+0 and a hot spare (or two). I'd only recommend it in cases
where there are a lot of writes - like mail and database servers. It'll
beat RAID5 by a good margin.
I'll be building a new mail server soon, with 6 15kRPM SCSI disks in it;
I'll have a go with bonnie, and see what we get for RAID1+0 and RAID5.
John
Maintained by the ILUG website team. The aim of Linux.ie is to
support and help commercial and private users of Linux in Ireland. You can
display ILUG news in your own webpages, read backend
information to find out how. Networking services kindly provided by HEAnet, server kindly donated by
Dell. Linux is a trademark of Linus Torvalds,
used with permission. No penguins were harmed in the production or maintenance
of this highly praised website. Looking for the
Indian Linux Users' Group? Try here. If you've read all this and aren't a lawyer: you should be!
