Craig Farrell (4/29/2011)
You mention you use simple backups. If you have full backups and need point in time restoration capability, can compellent's snapshots deal with this? I'm assuming it can't but as long as we've got an expert in the house... 🙂Also, are compellent's snapshots splittable, in particular does it file or drive snapshot? I don't want to be recovering 30-40 databases when I only need one off a logical array.
Great questions, Craig.
We only use Compellent's simple replays (snapshots/backups) for the database backup files produced by SQL Server's regular backup operations.
We use the Compellent Replay Manager generated replays for all of our databases. The difference is that the simple replays are not "transaction aware". The Replay Manager generated ones are and they ensure a consistent snapshot of a database's data and log files. Replay Manager uses Microsoft's VSS technology to accomplish this.
Either of the 2 types of Compellent replays can be used for point in time restoration to the degree of frequency the SAN administrator has set them up.
Compellent simple replays are file oriented. That is, they consist of a replay for a specific file.
Compellent Replay Manager replays are database oriented and are "splittable". We have several of these replays with more than one database included in them. I can restore a single database (both the data and log files) out of an aggregated replay.
The Compellent SAN is not drive/spindle oriented to an administrator. There is no way for an administrator to know exactly on which spindles his databases and/or other files are located. Not only is the information not available but the data is frequently in transit between defined "tiers", from 15K FC drives to SATA drives, or from RAID 10 to RAID 55, for instance.
The Compellent SAN is the closest thing to a black box I've ever seen. If I need to allocate disk space, I instruct it to allocate a certain amount on certain storage tier(s) that I've defined and the SAN just makes it happen.
LC