I would like to hear from anyone with real experience, success or failure.

We  have a single Vmware 5.0 host with a large amount of storage on a  single Linux virtual server, currently around 2TB and could go up to  12TB.  Other VMs too, but this is the big one.  I'm trying to come up  with a backup mechanism, keeping cost down, but which will do the job.    The users are processing satellite image data, using various FOSS  software.   They can stand extended backup and restore windows -- e.g.,  if it takes 10-20 hours to do a full backup on the weekend, that would  be OK.  File/directory level restores will be the norm, and if that  takes a few hours, that'sl OK, too.  The 12 TB is an internal RAID 5 LUN  with an Adaptec controller & 7 x 2TB 7200rpm SAS disks.

Since  I need file-level recovery, VADP type backups don't support that for  all OSes and filesystems.  So, I'm considering a conventional setup   with a Networker 7.6sp3 or newer client on the Linux VM and another VM  will be the storage node.  The Storage Node will use VmDirectPath to  connect to a tape system (like a Quantum Superloader 3) with a SAS 6Gbps  LTO5 tape drive.  16 LTO5 tapes at 3TB per tape should handle a full  backup.  The client &  storage node will communicate over the VMware  virtual switch, internal to the Vmware host.  We already have Networker  here, & I can use the existing Backup Server to conrol this  subsystem.

2 Major concerns:

Doing  some searching & reading, it seems there might be problems with  VmDirectPath access between the storage note & system.  If anyone  has any direct experience & can tell me something that does or  does  not work, I would appreciate it.

And, I'm banking on  very high performance for the network traffic between the client and  storage node, since it will never hit a wire,  but be entirely on the  virtual switch inside the Vmware Esxi 5.0 host.  Vmware says that's  supposed to be rather higher bandwidth than a physical Gigabit Ethernet  switch.  Seems plausible, I'm hopeful.  But I could be  wrong/disappointed.

I can use an existing tape autoloader to test with,  Just need to get a SAS HBA (PciE) -- any recommendations or warnings?