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agvonline's avatar
agvonline
Level 4
14 years ago
Solved

Fine Tune LTO 5 Tape Drive

Hi

I'm looking for some advice/guidance on getting the best performance out of my LTO 5 tape drive.

This is my setup:

HP 1/8 G2 LTO 5 AutoLoader - connected to...

HP DL360 G6 Server - via...

P212/256mb Smart Array Controller.

Then...

HP MSA2012i SAN - connected to...

another HP DL360 G6 - via...

HP 1800 8g switch.

There is also a HP 5308xl switch (with 1gb GBICs) connecting the two servers.

 

I have data stored on the SAN which I want to backup using the 1/8 G2 Autoloader, so the network/data route of this is...

MSA2012i -- HP 1800 8g -- DL360 -- 5308xl -- DL360 -- 1/8 Autoloader.

All network connections are 1gb.

 

I have Backup Exec 2010 G3. The default configuration for the LTO5 drive is used (64kb block size, 64kb buffer, 10 buffers, 0 high water). I also have 'Unknown Media Changer' set as Autoloader driver, and the latest Semantic DDI drivers for the tape driver.

As a test, to backup 18.3gb (34783) files of data, the data rate I get is 2,851mb/min.

 

I have done some tests increasing the block size and buffer count, but the best rate I can get is 2,890mb/min when I set block size and buffer count to 256kb. But is must be able to go faster than this...shouldn't it??

 

Any thoughts on this would be much appreciated.

Thanks

Andrew

  • Hi,

    I think that there may be some caching between the data store / reading and the writing.

    The caching will get a speed boost early on until the cache fills up, the estimation of how fast the copy is happening will seem very fast as it is writing to cache / memory and not disk, once the cache / memory has been used up the speed may then drop like a stone and the estimation has to drop very quickly and will keep dropping as it cannot achieve that cache rate again.

    It will eventually get down around the non-cache rate.

     

    Regards,

    Andrew

    Nebula Computer Services