Having such a limited throughput to your LTO2 drives points to very slow
read capability of your disk system.
I would suggest that first of all you figure out why your disk (backup)
device is not capable of providing higher read throughputs.
You may have to check the service time for your device and the total
throughput read+write.
It might very well be that if you have multiple processes (save streams)
writing to the same device you are reading from with only one stream
(the staging process), the writes will monopolize on the device.
I would try to test the read throughput by staging at a time that no new
backups are directed to that disk device.
Itzik 

> -----Original Message-----
> From: Legato NetWorker discussion 
> [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On Behalf Of Mark Davis
> Sent: Wednesday, September 28, 2005 19:00
> To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
> Subject: [Networker] Migrating data from staging disk to LTO3 tape
> 
> We are looking at upgrading the drives in our tape library to 
> LTO3 technology. My concern is with cloning/migrating data 
> from our staging drives to tape. With our present 
> environment, the throughput rate to our existing LTO2 drives 
> ranges between 10 MB/sec to 20 MB/sec. With the
> LTO3 drives rated at 60 MB/sec, I am worried we will get into 
> some serious "shoe shining" with the LTO3's, due to our 
> inability to reach the streaming rate. This shoe shining, 
> meaning forcing the tape to continually stop, reverse, and 
> move forward again during recording, would cause significant 
> wear and tear on the media and the drives.
> 
> On area where I could see improvement would be to send more 
> than one clone/migration session to a single tape device. 
> Does anyone know if this is possible?
> 
> Is anyone presently cloning/migrating staging disk to LTO3 
> drives, and have there been any issues?
> 
> Thanks very much.
> 
> Mark Davis
> --
> Mark Davis
> Legato NetWorker Support - I.T.S
> University of Western Ontario
> email: davism AT uwo DOT ca
> 
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