ZFS RaidZ2 with 24 drives?

[Bob Friesenhahn]

On Fri, 1 Jan 2010, Bernd Walter wrote:
>
> There are many possible reasons why this won't happen.
> One of them is a simple write failure, which can't be reported back
> to the filesystem, because not even a cache flush fails.

For most RAID systems (and for ZFS) it is best if write failures are 
tossed because there should be a redundant copy somewhere else. 
Write failures usually indicate a completely failed disk since modern 
disks include their own bad-block management.  The most important 
thing for ZFS is that transaction group writes are written in order, 
as demarcated by transaction group cache sync requests.  Otherwise you 
get a scrambled pool which may require an expert human to untangle.

> The main problem I see is that such controllers won't tell about
> their strategy, so you are left in the dark.

That is unfortunate.

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