BackupExec 12.5 and SAN connected TS3500 LTO4 Tape Library.

Hi Slaine,

Whoever told you that doesn't know what they're talking about.
Firstly, if all your drives are connected to 1 FC switch and it dies, there go your backups until you can actually get it working again or replaced.
You would need to do the following:

1. Add the second FC switch to your SAN. It will either join the fabric, or be in its own fabric. Not an issue if it is in its own fabric.
2. Connect an Interswitch Link (ISL) between the FC switches in case you want some devices to move data between switches (in case of failure/only having 1 HBA in a server for example).
3. Take 1 HBA from your server and plug it into the new switch. Unplug 2 drives from the current FC switch and plug it into the new FC switch. Zone your ports (WWN is the best). That will be robotics + 2 drives/FC switch paired with the FC HBA of the corresponding server's HBA that is attached to that switch.
4. Check Windows Device Manager to see that it sees the 4 drives.

Having 2 FC switches = redundancy on your fabric, and your backup environment. We use this at our Head Office with no issues. In our case, it is an HP StorageWorks MSL6060, with 2 HP StorageWorks (Brocade) 4/16 FC switches. It is most definitely supported.
BE doesn't care how the drives are assigned...just that Windows can see them so that it can see them. They will be detected as having 4 drives in BE anyways...

Hope this helps?

Thanks for you reply CraigV.

I am being told this by our Storage and Backup Management Team in Spain. I am in the UK.

they sent me this today:

"We tested the configuration you are stating( 2 SAN Switches ) with the v11.d version of BE and the BE server was not able to manage the drives properly due to a registry problem of the Windows OS. We have the v12.5 currently installed and for this version Symantec has been very clear: “2 SAN fabrics aren’t supported in Backup Exec"

Is this correct?

Er, wrong on both accounts...we had 11D. Our Head Office has a bottom fabric, and a top fabric. No idea why, I would have made it 1.
As long as you are zoning your server's HBA to 2 drives assigned to switch 1, and the other HBA in the server to the remaining 2 drives on switch 2, Windows is going to see 4 drives.
The ONLY thing I can think of that will mess this up is if the library doesn't have 2 network storage routers...basically the robotics controlling the library. The HP StorageWorks MSL6060 we use at the HO does have 2, so it isn't a problem.