Multi-host SCSI

[Twa]

Recently set up BackupExec 11d on Windows Server along with an Ultrium TD3 LTO drive. So far it's working perfectly to backup a single server.

However, when we bought our tapedrive along with a new server (at Dell), we were advised to use multi-host SCSI to connect our two servers along with the tape drive on one SCSI bus. Connected this and it seems to work alright (tape drive is being detected on both systems), but I'm unsure how to proceed next.

I've searched for multi-host and multi-initiator SCSI on google and Symantec's KB, but haven't been able to find a thing.

I think it'll probably work if I also install the full BackupExec suite on the second server and time the backup sessions and schedule them in a way where one won't start while another is running, but I'm sure there is a better way to do this.

The way I pictured this would work is that both servers know they both share the same tapedrive and coordinate the backups together where one would start it's backup after the first one is done, or simply both write to the tape drive based on 1 backup set at once.

What's the best way to go around this? I'd prefer to have one single backup set for both servers, and preferably only install the backup agent on the second server.

[Lou_Buffetta]

Hi Twa

Traditionally, Backup Exec recommends that you place the tape unit on its own SCSI card - not just a channel but entire card. But what you're trying is new technology. I couldn't locate any details on multi-host or multi-initiator SCSI either. These are definitely not in our Hardware Compatibility List.

The good news is that both servers detect the tape unit. You will need to install Backup Exec on the second server for that box to backup to the tape unit. That should not be a problem as you most likely have a site license for Backup Exec.

If you want to coordinate the two servers and backup jobs, you may want to check out our "Central Admin Server Option."

When CASO is installed in a Backup Exec environment, one media server, known as the
central administration server, delegates jobs to managed media servers across the
network. Job delegation is the automatic load balancing of jobs across available managed
media servers in the CASO environment.

Check the on-line Admin Guide (Appendix A starting on page 779) at this location

     C:\Program Files\Symantec\Backup Exec\BeAdmin_en.pdf

However, this is a paid-for option. If you want to forego the option, then you will need to schedule your backups just as you outlined in your orginal post.  

With all that said, you can simplify everything by installing the Remote Agent on the second box. Use just the one Backup Exec server to backup both machines to the tape unit. This will only require one backup job and elimiates the need for coordinating two media servers and mutliple jobs. It's also the least expensive way to go.

[Twa]

Hello,

Thank you for the quick response. Our tape drive is on a dedicated controller on both servers already.

We only have a single server license of BackupExec, not a site license, as our reseller assured us we would only to run BackupExec server on one system.

The idea was that the backups would be done as with backup agent on the other system, but the data would be transfered directly to the tape drive over the SCSI bus instead of over the network.

If Symantec doesn't support or has never even heared of this setup with two servers on one SCSI bus (I am unsure if the correct name for this is multi-host or even multi-initiator, by the way), I'm quite curious how our reseller came to suggest this setup to us. I was also told by another person that, in the fibre channel SCSI world, a setup like this is quite common, and should also be possible with traditional SCSI. It also sounds like a logical setup, for systems that require fast data throughput.

If this is really impossible, I think I'll go for the Backup Agent solution you have suggested instead.

[Hywel_Mallett]

I think your reseller is misguided.

Backup Exec sort of has the functionality you are describing, with the San Shared Storage option, but as the name implies, this is for when your media servers and backup devices are attached to a SAN. It also requires you to have Backup Exec installed on each server.

I'd get a Remote Agent license, make sure you have a fast network connection, and backup the other server over the network.