Like everyone else, I'd like to have my shop's backup traffic avoid the IP network as much as reasonable. SAN Client, a component of the Enterprise Client introduced with NetBackup 6.5, is a solution for that objective that intrigues me.
Previously, Veritas' only solution to having a client's backup traffic avoid the IP network was the SAN Media Server product. SAN Media Server, which also comes with the Enterprise Client, gives the client media server functionality. So, with SAN Media Server the client itself directly connects to the backup device, and no longer needs to send its backup traffic over the IP network to a "general purpose" media server.
I have always been averse to the SAN Media Server solution, because: 1) media servers by their nature are subject to all sorts of disruptions
coming from tape drives and tape media, which occasionally require the media server's NetBackup daemons to be recycled or even for the host to be rebooted. Making the host of an application a media server and thus subjecting it to the same disruptions would be unacceptable; 2) there are support issues for the client OS, if that client's platform doesn't fall under the expertise of the backup support team. For example, in my team we are Unix admins by background. So, we're not entirely comfortable turning a Windows client into a media server; 3) In "politically charged environments", the SAN Media Server product can become the scapegoat for any problems that arise with that host; 4) There are concerns about scalability. How many clients turned media servers can you have, all sharing backup libraries, before things "break down"?
With the SAN Client product, the client sends its backup data to a media server. However, that data is sent via SCSI over
the SAN, not via IP over the IP network. This is potentially a great solution, as it would allow us to divert backup traffic from the IP network on a large scale.
The lack of publicity that I've heard from this product, though, leads me to believe that there have been problems with its actual implementation, that it has turned out to be less scalable, more problematic, etc than was originally anticipated by Symantec. But rather than continue speculating in a vacumm, I'd like to get some feedback from backup engineers who've worked with this product.
Some questions I have for those who have deployed the product:
1) How many clients do you back up via SAN Client?
2) How many media servers run SAN Client backups?
3) Is there a rule of thumb SAN Client to media server ratio that you follow?
4) I understand there are restrictions with the media server HBA, and that there are particular drivers for this product. Did these HBA/driver
issues pose a problem in the implementation?
5) Any other "gotchas" with the product?
6) Do you feel that SAN Client has helped significantly in reducing the amount of backup traffic on the IP network?
Any feedback that I can get on the SAN Client product would be most appreciated. Thank you.
Howard
