We are backing up a 270c nightly with Netbackup via NDMP to a dual drive
LTO3 machine (only one drive is used for to backup the filer). There are
2.25 TB on one head and 1.1TB on the other. For a full backup it takes
about 10 hours to write to tape, which I don't think is too bad (larger
volumes hit 31200 KB/sec reported by Netbackup), but the differentials
take 5 hours to run,even though the delta on our data is very small.
 
 I suspect this is more of a Netbackup issue then a filer based one but
wanted to throw it out there incase there was something I should look at
on the host side. This is over a normal gigE switched network connection
with the default settings on the filer, network-wise. We are not using
virtual interfaces, both heads have a single 1 gig connection to the
LAN. Any suggestions or inventive flames are welcome.
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