Subject: [Veritas-bu] Slow performance 4.5


We have an STK 9740 Library with 4 9940A drives and I am experiencing what I
believe to be some bad performance of the transfer rate.  I am backing up
the master server as a test so there is no network traffic that would come
into play.  We are getting about 4 Mb/s transfer to the drives.   We are
fiber from the host direct to the drive.  I would think that the speed would
be considerably higher than that.

        That is definately slow.  What type of host?  What disk subsystem
        are you reading from?  How many disks?  Is the disk subsystem fiber
        also and using the same hba?  What is the MPX value of the backups?

        I would consider changing the backup to use only one drive and see
        if you get higher throughput.  We have found that sometimes we slow
        down our drive performance by using more drives.  The overall
performance
        stays the same, but each drive decreases in performance.  This says
        that something else such as the fiber link or the disk subsystem
        is the problem.

Am I off by thinking that? Or is there something that could be throttling
the drives down..
        
        See above.

        Ken Sibley
        Sr. Unix Admin
        Accor Economy Lodging
        ksibley AT accorel DOT com
        469-737-3370

Any info would be greatly appreciated.

Thank you,

Bryan Moore
Senior UNIX Systems Administrator
Scripps IT Operations


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