HPC and zfs.

Bob Friesenhahn bfriesen at simple.dallas.tx.us
Mon Feb 6 17:39:18 UTC 2012


On Mon, 6 Feb 2012, Michael Fuckner wrote:
>
> Another thing to think about is CPU: you probably need weeks for a rebuild of 
> a single disk in a Petabyte Filesystem- I haven't tried this with ZFS yet, 
> but I'm really interested if anyone already did this.

Why would a disk rebuild take longer for a petabyte filesystem rather 
than a tens of gigabytes filesystem?

The time to rebuild the disk primarily depends on the RAID type used 
for the zfs vdev (mirrors, raidz1, raidz2, raidz3), how many disks 
there are in the vdev, the degree of fragmentation, the amount of data 
stored on that disk, and the disk seek times.

In a huge system, it makes sense to be more conservative about the zfs 
vdev design, and use more vdevs with fewer disks per vdev.  Using 
anything less than raidz2 would be an error.

Bob
-- 
Bob Friesenhahn
bfriesen at simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/


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