Question on how RAID works

Karl Zander KZander at CommPartners.com
Wed Oct 8 17:10:01 CDT 2003


We have a PE 1650 running RH 7.3.  It has 3, 36 GB drives in RAID 5.

One drive in the container went off-line.  The server crashed: kernel 
panic, I/O problems etc.  Dell's phone support engineers where very helpful 
and we got the drive back on-line and the container rebuilt.   Physically 
the drive seems to be OK.

My question is about RAID 5.  If one drive does fail, aren't the remaining 
two drives supposed to be able to carry on?  I realize nothing is 
perfect.  Certainly my own case shows there are times when a single drive 
failure can take down the entire server.   For my own general edification, 
how reasonable is it to expect RAID 5 to carry on with a single drive 
failure?  50-50?  80-20?   Just looking for some general guidelines so I 
set proper expectations with the powers-that-be.

-Karl




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