Scott Burns said:Dan Goodes wrote:
Just to clarify here, we (PlanetMirror) lost a number of disks in a raidStill offtopic, but I read the informix newsgroup, and there is a
array, and are working on restoring service. As you noted, this means
that RH and Fedora are missing, among others (albeit temporarily, but I don't
have an ETA at this stage).
resident who posts regularly on the evils of RAID5 - mainly that no
matter how many disks you have, if two disks die, the second before the
recovery of the first is complete, you lose everything. I'm just
curious to see if you used RAID5?
Of course if both disks of a mirror set die you lose everything, too.
In both cases, you can using either linux software raid or most hardware raid cards have it, is have one, two, or more hot spares as part of the raid.
Example,
A computer with 4 - 100GB hard drives in a RAID 1 (mirroring), set up a mirror with 2 hot spares. Total storage - 100GB, but you can have 3 drive failures and the system can keep running.
A computer with 4 - 100GB hard drives in a RAID 5 (parity) set up, 3 drives are active in the RAID 5, 1 hot spare drive, Total storage 200GB, actually a little less due to overhead. In this configuration, one of the drives in the raid fails, the hot spare becomes active, the raid rebuilds, and you replace the dead drive with a fresh drive and this drive becomes the hot spare. In this case, you can have 2 drives fail and the system can keep going.
If you want to do something like this, I recommend 3ware raid cards, this is how I have my file/print servers running samba working at the schools I work at.
Eric Feldhusen
