PVFS and Software RAID

Walter B. Ligon III walt at parl.ces.clemson.edu
Mon Jan 22 11:21:14 EST 2001


--------

As far as I know, neither approach will work.  The only way I know to implement
redundancy is to put two drives in each node, use software RAID to create a
redundant system on each node, and then use PVFS to get parallel data 
distribution.

This will protect you from disk failure, but not from node failure.  In the 
event
of node failure you would have to repair or replace the node and bring it back
up with disks intact.  This prevents data loss, but does not insure high 
availability.

If the software RAID drivers have recently gained the ability to do mirroring
across the network, I didn't know that and I'd like to hear about it.

Walt

> I'm sure this problem has been discussed here, but maybe we could go over
> it again.
> 
> Problem: I have four boxes with a 9 GB file system (/dev/hda7) in each
> box. I would like to use them all to create one 18 GB file system that is
> redundant. Is it better to use PVFS on two pairs of drives to create 2 18
> GB file systems and then use Software Raid to make these redundant. Or is
> it better to use Software Raid to make 2 9 GB redundant file systems and
> then create the 18 GB file system with PVFS?
> 
> Kevin.
> 
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-- 
Dr. Walter B. Ligon III
Associate Professor
ECE Department
Clemson University



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