> I have recently inherited a Networker 7.5.1 enviroment with a 3.8T 3600 user 
> home folder that recides on an NS480 with a fiber attached L700 (7drives LTO3 
> ,500 slots) Tape Library to use to back it up. The problem is that no matter 
> how my team has tried to back it up, it takes 30+ hours. I am wondering if 
> anyone else out there has a similar config that might be willing to save us 
> some brain damage of retrying every method under the sun, currently we have 
> 3600(1 per user) savesets running NDMP, which is not great but we at least 
> get some success. My other team members state that trying to do it as 1 
> saveset just timeouts or crashes at 30+ hours and never finishes. We are 
> currently using checkpoints to do the daily INC then a weekly full to tape 
> but can't seem to get it in to a <23 hr window.
> Oh and the obvious of breaking them into different file systems has been shot 
> down.



3.8TB in 30hrs is the equivalent of 17MB/sec ??  Can someone verify this 
number?  If my math is correct, this is very slow for an NDMP drive, and I am 
assuming that the drive is connected to the Celerra.  i.e, the data is not 
going through the LAN before being written to the NDMP drives.

Assume that we are using NDMP configured drives that are connected directly to 
the filer, I have seen LTO-3 drives can write (conservatively)  120MB/sec.  
Again if my math is correct, then backing up 3.8TB should take approx 8.8 hours.

If you can also backup 4 streams in parallel (Celerra allows for max of 4 pax 
threads that allows for 4 backup streams), and assuming that each stream backs 
up equal amount of data, then this should reduce the backup time to approx 2.2 
hours.  In theory.

So...  is there 4 drives connected directly to your NS40, (scsi or fiber)?

You mention that you do daily INC backups.  Incremental backups are not allowed 
with NDMP backups.  You are only allowed to specify full or differential type.  
If you specify incremental, then the filer will use level=full, because the 
filer does not know what is incremental.

Make sure you have Snapsure enabled on your Celerra, otherwise this can cause 
your backups to fail.

You generate multiple streams by spreading the data across multiple partition.  
Not sure why you would not want to take advantage of this, especially since you 
are trying to reduce the backup time.


Well, if you are limited to just one stream, then make sure that The NS40 is 
writing directly to a locally connected drive to the Celerra.   If possible, 
replace the lto-3 with a faster drive lto-4, 5, 6...  I know they are more 
expensive, but so is the time needed to backup.

Finally, see if EMC can do a health check on the NS40 to make sure it is 
performing optimally.

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