RAID controllers

[Daniel Foster]

> What is the failure rate of RAID - not from the hard-disks, but
> either from the RAID controller - or the motherboard or non-hard
> disk part of the server?

To be honest I'm not sure, but RAID is certainly a step in the right
direction.  Mirroring site with the right DNS settings can make another
server take over within 5 minutes (or however long you specify) of one
disappearing from the network.

> As an aside, is the following reasonable as a "budget" 
> substitute for a RAID system which assumes complete 
> system failure of either a SCSI card - hard disk or 
> motherboard? acceptable - but not too much)
> Generic PC Hardware and: 
> "SCSI Card one" with two external SCSI hard-disks - 1a and 1b
>    First Hard disk  - for Web and FTP data
>    Second Hard disk - for system, web and ftp logs
> "SCSI Card two" with 2 external SCSI hard-disks "rsyncing" the data 
> at regular intervals from SCSI Card 1

I'd have thought there was a purely RAID solution.  Use a mirroring for of
RAID, with the mirrors on a separate controller.  That way, a one
controller failure could possibly be coped with.  I'm not a RAID expert,
but I don't see any reason why(in throy at least) it wouldn't work.

> (plus a tape backup device - with offsite tape storage)

Of course, but backups are kind of a separate topic...

-- 

Daniel Foster - daniel at 34SP.com