zfs discuss - Nov 2007 - Securing a risky situation with zfs

Hi,
we''re having a bad situation with a SAN iScsi solution in a production
environment of a customer: the storage hardware may panic its kernel because of
its software fault, with the risk of loosing data.
We want to give the SAN manufacturer a last chance of correcting their solution:
we''re going to move data from the SAN to new fresh scsi-attached disks,
for the time needed for them to find the bugs. Once they''ve certified
us the solution, we will move back the data onto the SAN.
Here comes the issue: we can''t risk our customer''s data to be
again on a possibly faulty SAN, so we were thinking about reusing the
scsi-attached disks as part of the zfs pool of the SAN partitions.
The basic idea was to have a zfs mirror of each iscsi disk on scsi-attached
disks, so that in case of another panic of the SAN, everything should still work
on the scsi-attached disks.
My questions are:
- is this a good idea?
- should I use zfs mirrors or normal solaris mirrors?
- is mirroring the best performance, or should I use zfs raid-z?
- is there any other possibility I don''t see?
Last but not least (I know the question is not pertinent, but maybe you can
help):
- The SAN includes 2 Sun-Solaris-10 machines, and 3 windows machines....is there
any similar solution on the win machines?

Thanx for any help
Gabriele Bulfon.
 
 
This message posted from opensolaris.org

On Tue, Nov 13, 2007 at 01:20:14AM -0800, Gabriele Bulfon wrote:
> The basic idea was to have a zfs mirror of each iscsi disk on
> scsi-attached disks, so that in case of another panic of the SAN,
> everything should still work on the scsi-attached disks.
> My questions are:
> - is this a good idea?
it''s a better idea than just trusting your flaky SAN.
> - should I use zfs mirrors or normal solaris mirrors?
ZFS gives you the big advantage of on-the-fly data checksumming; 
that''s very helpful compared to disksuite mirrors.
> - is mirroring the best performance, or should I use zfs raid-z?
mirroring is almost always going to give you the best performance.
> - is there any other possibility I don''t see?
call the comcast hammer lady [1] and ask her to come take care
of your SAN.
> - The SAN includes 2 Sun-Solaris-10 machines, and 3 windows
> machines....is there any similar solution on the win machines?
none that i''m aware of; windows does have software mirroring, of 
course.  Make lots of backups :).  



danno
--
Dan Pritts, System Administrator
Internet2
office: +1-734-352-4953 | mobile: +1-734-834-7224

[1]
http://www.washingtonpost.com/wp-dyn/content/article/2007/10/17/AR2007101702359.html