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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Mark Harvey wrote: > > I have no idea how to test this - the program is provided by our IT suppliers > and it's workings are a mystery to me. And to them sometimes it seems. I think you are going to have to know something of the innards of the program to run an upto date hot standby. In particular how data is committed to disk, and when it is safe to copy that across. Sounds like a database application to me, anything in there look like a database process? Usually you know if trivial hot standby solutions won't work reliably if you have to stop the application (if only briefly) for tape backups. With hardware RAID devices, these can be shared across boxes, resolving some of the disk issues (although you move away from hot standby). In this scenario one or more RAID boxes are "shared" between computers, and if the computer fails, just switch off broken one, switch on standby (and assuming the application can recover from where it left off!!!!! Probably can if the transaction handing is solid), and you are away. Of course this moves the disks (most likely thing to fail) outside of the the computer (less likely to fail), so it is not uncommon to mirror across RAID arrays, and connect using long optical fibre connections (avoids some electrical probems, such as may happen if one RAID array is struck by lightening). I like hot standbys, cheap and easily understood, little risk of discovering some oddity of hardware, but you need to understand the application. How are current back-ups handled? This is usually a big clue. -----BEGIN PGP SIGNATURE----- Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQE/g11yGFXfHI9FVgYRAlKbAJ9o7ECUl8g5HDBNnwWXbS02Z8jAVQCeIguk Nh1D+4m+s811BOtivqPA1xQ= =Ehf6 -----END PGP SIGNATURE----- -- The Mailing List for the Devon & Cornwall LUG Mail majordomo@xxxxxxxxxxxx with "unsubscribe list" in the message body to unsubscribe.