On Mon, 20 Jun 2011, Nicholas Tang wrote:
> There is a quirk in their reporting of space and snapshot reserve space and
> things like that - if you use the snapshot reserve, it reserves dedicated
> space for snapshots, but doesn't mark that space as used in your free
> space.  I made the mistake of setting the snapshot reserve too high and we
> had a bit of panic when we lost the ability to write to the device with a
> "quota exceeded" error when we had no quotas.  Fortunately, now that we know
> how it works (including the fact that you can write snapshots even when the
> reserve is exceeded, that's just a minimum guarantee but they can grow as
> large as you want them to) we've had no issues there.

Interesting.  It sounds like they're redirect-on-write, similar to NetApp, 
rather than copy-on-write.  The last time we spoke to Isilon, they 
seemed...well, less than sure what technology they used for their snaps, 
but they seemed to indicate they were COW.  I was surprised, since it's 
"one filesystem".

-Adam

_______________________________________________
Tech mailing list
[email protected]
https://lists.lopsa.org/cgi-bin/mailman/listinfo/tech
This list provided by the League of Professional System Administrators
 http://lopsa.org/

Reply via email to