Chadwick Leung wrote:

> Greeting!
> 
> I have installed a Sun L8 autoloader which replaces a Sun L9 model . The 
> L8 has been successfully installed and can operate without problem. 
> However, the average throughput is just up to 5 MB/sec under Netbackup 4.5.
> 
> I tried to TAR a 1.2 GB file direct to the LTO2 tape, it took about a 
> minute. Under Netbackup, backing up the same file take about 4 mins. 30 
> sec.
> 
> Any idea?

You must multiplex the backup stream to get maximum throughput.
I have two L5500's with 10 LTO Gen 2 each running across 2GB single
mode fibre and am able to get upwards of 30MB/sec on 8 drives at once.

I've seen problems where backup streams slow down to nothing and
have not been able to figure it out.  It hasn't been a problem
lately, so I'll assume it was the fibre and not the drives or NB.

Right now, I'm running MAX_MPX 6 and NUMBER_DATA_BUFFERS 16, and
SIZE_DATA_BUFFERS 262144.  On average I see a range of about 12MB/sec
to 30MB/sec.

Direct tar to tape will be slow, I tested this an found it too about
2 hours for 10GB.  But that was back in the beginning before we made
some infastructure improvements.

Hope that helps.

-- 
Dan