off-host backup of a storage array LUN snapshot

[rabrab2]

Hi,
I've been going through some information and considering switching to off-host backups using Dell EqualLogics at the backend to take snapshots and back them up.

I've been reading this brief:
http://eval.symantec.com/mktginfo/products/White_Papers/Storage_Server_Management/wp_be_sfw_quick_re...

And also came across this video:
http://www.youtube.com/watch?v=GsPUx6UzzeM

One thing that isn't clear to me: how does backup exec know which LUN snapshot to backup? The video shows the EqualLogic management console displaying the newly created snap, but it's not clear how backupexec in the background knows to take data off that LUN. I'm assuming this uses the Windows Volume Shadow Copy Service (at least according to the brief).

Is this some proprietary API between the BackupExec agent and the EqualLogic hardware provider? Would this work for any hardware provider? If this is a well known API - can someone provide the name so I can google it?

Thanks,
Amir.

[teiva-boy]

 You must install on the host that the LUN is assigned to, the EQL tool.  They install a VSS provider of their own.  

When you do your backup, the tools actually call the snap, and ultimately that snap is mounted by BE to be backed up.  It's actually really the EQL API's that do the heavy lifting.

[rabrab2]

Thanks for the response. So I'm trying to understand how that mechanism actually works. I have EQL HW provider installed on the windows host. BE agent asks the HW provider to take a snap. It's using transportable snapshots so that the BE media server (?) can mount the snapshot directly instead of using the host. Is this correct? Does that mean that the BE media server must impelement some kind of EQL knowledge/procedures? Is it mountain an EQL snapshot directly off the EQL array?

Thanks.