- Does a hot backup (as described on http://www.netapp.com/tech_library/3049.html) present any restoration problems?
The only caveat to this is if you're trying to use SnapMirror as well, which won't replicate 'manual' snapshots. Kind of a big gotcha when trying to really leverage the filer's features.
- Hot backups are as close to "live" as you're supposed to come, but it seems to me that a nice extra bit of paranoia would be to take snapshots 2-3 times per day of the live database. The image would be consistent, and Oracle would come up off of it as it would from a crash
Kinda. In practice, I would only consent to a clustered pair before running a database on top of it (just as you'd would want redundant paths and controllers in a local raid or jbod). However, if you spread your database out across these to take advantage of the added performance as well, then a 'live' snapshot is unreliable, as even with damn precise timing, both filers still won't take them in the same instance of time.
I've so far been very impressed with my filer. Oracle over NFS sounded outright dumb to me at first, but damn if it isn't faster than local disk.
I haven't seen the same, but thankfully the database running against them doesn't have heavy disk i/o requirements. What were the specs of the local disks you were comparing against -- was it anywhere close to an equivalent priced? I've found that a 760 runs out of CPU around ~18MB/s of sequential writes, not to mention the processor penalty from NFS client overhead.
One thing that did console me was the 'safety' of doing this over NFS, to a tightly-integrated box like the filers. We had run across problems with buggy FCAL drivers that were successfully returning from a write(), even when out of cmd tags. The catalyst was two-fold, with a failing hub taking down a poorly-laid out loop .. This caused for much corruption and pain, which thankfully under the realm of filer NFS is extremely unlikely (given that filer like to panic when things look bad, and NFS clients love to hang), and otherwise NFS is nicely handshaken.
..kg..