On Tue, 2 Mar 2010, Brian Kolaci wrote:
What is probability of corruption with ZFS in Solaris 10 U6 and up in a SAN
environment? Have people successfully recovered?
The probability of corruption in a "SAN environment" depends entirely
on your SAN environment. With proper design, the probability should
be "zero". If it is non-zero then there must be a design defect in
your SAN hardware which is liable to do harm at any time (aka "snake
in the grass").
In this environment the redundancy is performed at the hardware level, not at
the host. So there's no chance of self-healing here. Yes, its been
discussed, but because of the legacy storage environment thats shared with
other non-ZFS systems, they require redundancy at the hardware level, and
they won't budge on that and won't do additional redundancy at the ZFS level.
That is unfortunate. In this case, probabilty of failure increases
from "zero".
So given the environment, would it be better for lots of small
pools, or a large shared pool?
I think that a larger shared pool will be more satisfying and less
wasteful of resources. However, a large pool written to a single huge
SAN LUN suffers from concurrency issues. ZFS loses the ability to
intelligently schedule I/O for individual disks and instead must use
the strategy to post a lot of (up to 35) simultaneous I/Os and hope
for the best.
Bob
P.S. The term "zero" is quoted since it does not account for Murphy's
Law.
--
Bob Friesenhahn
bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/
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