Coming ADV_FILE changes

I had been aware for a while from an NDA conversation that these changes were on the way, but of course have not been able to discuss them.

However, with EMC opening up discussion on the EMC Community Forum – i.e., out in public, I now feel that I can at least discuss how excited I am about the coming ADV_FILE changes.

For some time I’ve railed against architectural failings in ADV_FILE devices, and explained why those failings have led me to advocate the use of VTLs over ADV_FILE devices. As announced on this thread in the forums by Paul Meighan, many of those architectural limitations are soon going to be relegated to the software evolutionary junkpile. In particular, EMC have stated in the forum article that the following changes are on the way:

1. Volume selection criteria becomes intelligent. NetWorker currently uses the same volume selection criteria for disk backup as it does for tapes. This means that the oldest labelled volume with free space on it always gets picked first, and subsequent volumes get picked following this strategy. This has meant that backup administrators have continually fought a running battle to keep the original disk backup units staged more regularly than others. Instead, NetWorker will now pick ADV_FILE volumes in order of maximum capacity free, which will free a lot of backup administrators from the overall pain of day to day capacity management.
2. Savesets can span advanced file type devices. Finally, the gloves are off! With the ability to have savesets cease writing to one disk backup unit and move over to another, NetWorker ADV_FILE devices will be able to serve as a scaleable and transparent storage pool, backups will flow from one device to another in exactly the way they always should have.
3. Session changes. To reflect round-robining best practices, the default target sessions for disk backup units will drop from 4 to 1.

When we add together the first two changes, we get powerful enhancements in NetWorker’s disk backup functionality. Do other products already do this? Yes, I’m not suggesting that NetWorker is the first to this, but it’s fantastic to finally see this functionality coming into play.

Until this point, NetWorker has suffered the continual challenge with disk backup of constant administrative overheads and trying to plan in advance the best possible space allocation technique for disk backup filesystems. Once these changes come into play: no more challenge on either of these fronts.

Folks, this is big. Yes, these changes should have come a long time ago, but I’m not going to let the delay get in the way of being damn grateful that they’re finally coming.