[BBLISA] Tape backup

[Brian O'Neill]

LTO-3 _is_ 400GB/800GB. I don't think you'll see drives differing on 
that. LTO-2 is half that capacity, and LTO-4 is twice it - they keep a 
fairly steady doubling of the capacity in the LTO specs. Whether 400/800 
is enough for you may depend on frequency and level of the backups (full 
  vs. incremental backups).

The problem with LTO-3 and up is that most standalone systems alone 
can't keep up with tape drives. If the system can't keep the data fed to 
it fast enough to keep the tape moving, it has to stop and start the 
tape, which hurts performance further and tends to wear the drive 
components faster (the "shoeshining effect"). If the drives are in a 
raid array, that might be better. I generally wouldn't recommend it for 
a standalone system though.

I have two LTO-3s connected on their own SCSI bus to a dual-core Dell 
1950 server with a VTL connected via FibreChannel. Initial backups go to 
the VTL, and then they are pushed to one of the tape drives when the 
system is idle. I only use one tape at a time, and still the system at 
times the tape has to pause. However, the average throughput is still 
way faster than LTO-2.

The main problem is that hard disks are growing much faster than tape 
capacities. For standalone uses a removable drive unit of some form 
would probably be more effective.

Scott Ehrlich wrote:
> For a machine with 750 GB x 4 SATA drives (connected to SAS backplane) = 
> 3 TB (roughly), what would be a recommended native/compressed lto3 
> [half-height] capacity drive to use for backup?  This is a standalone 
> desktop.
> 
> I am considering Windows native backup, if that will work with a tape 
> drive.
> 
> Some of what I've seen are 400 GB native / 800 GB compressed.  Normally 
> I'd think that would fill quickly, but with tape drive technology and 
> software, another part of me thinks it may last longer than I expect.  I 
> look forward to getting educated here.
> 
> Thanks.
> 
> Scott
> 
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