tape drive will use LOCATE BLOCK to first file to restore, then search from 
there.





wdlb5359 wrote:
> What are people using for the fragment size on LTO4 (or I guess LTO3) with 
> NBU 6.x?
> 
> I ask because the default is 1TB, i.e. more or less don't fragment.
> 
> The argument for a large fragment is that the backup doesn't have to stop 
> so often as it does briefly at the end of each fragment to update the 
> Master, and also the inter-fragment file markers waste space..though 
> that's hardly a consideration on such large tapes now.
> 
> The argument for a small fragment was that the tape can position at full 
> speed to the file marker for the appropriate fragment for a restore, 
> rather than reading the tar file from the top at read speed, which for a 
> large tape could be a very long time.
> 
> We used to (dating back to DLT7000) set a 2GB fragment, as back then this 
> was thought a good idea in case you wanted to dd the tape to disk and read 
> it without NetBackup.  UNIX file systems did not take files > 2GB.  Well I 
> can't say we ever tried it and it's a silly small size now.
> 
> But what are people using - 100GB?  200GB?  Does it really make a 
> difference...
> 
> William D L Brown
> 
> 
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