Re: Max of 20MB/sec through FC attached LTO tape drive? Overland neo 2000

From: Adam McDougall (mcdouga9@egr.msu.edu)
Date: Fri May 09 2008 - 18:19:19 EDT

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    Nope, I may have experimented with it on a volume not in production
    once, but I never tested backups in combination with it. The only
    options I have enabled anywhere on volumes are nosnap, nosnapdir, and root.

    Holloway, Chris wrote:
    >
    > I have seen the minra option on the volume have a major affect on
    > backup speed. Have you got it set to minra=on on any of your volumes?
    >
    > Cheers
    > Chris
    >
    >
    > ----- Original Message -----
    > From: owner-toasters@mathworks.com <owner-toasters@mathworks.com>
    > To: Toasters <toasters@mathworks.com>
    > Sent: Fri May 09 16:02:14 2008
    > Subject: Max of 20MB/sec through FC attached LTO tape drive? Overland
    > neo 2000
    >
    > Asking here because we don't have current Overland support for the fibre
    > channel card and I would guess it is more of a problem with the card
    > rather than netapp (we only used the FCO with a netapp), but maybe
    > someone has encountered this...
    >
    > Around 2004 we bought a Overland Neo 2000 tape library with the FCO VIA
    > scsi to FC converter board, and we got at most 20 or 25MB/sec through it
    > (per tape drive) depending if we were writing or reading. This is both
    > with NDMP dumps from the filer disks to tape, and also across the
    > network into the filer to tape with NDMP. The backup software is
    > Bakbone Netvault. Last year we tried attaching this library to a Unix
    > host directly with SCSI and our speed almost doubled. I was floored,
    > and shocked that we spent so many years missing out on performance,
    > although 20-25 was the best I've seen anyone report for LTO2 so I never
    > expected more.
    >
    > Recently we bought another Neo 2000 with LTO4 drives, and I decided to
    > move the FCO card over to it and try again, hoping maybe there was a
    > misconfiguration, but I could not find any and it still acts as if there
    > is a mystery cap on the speed of 20MB/sec (it averages 18-19 after it
    > gets going). I've been all through the configuration of the FCO card
    > and it is set to 160M/sec per scsi bus, tried with and without domain
    > validation, and I even got the FC channel to operate at 2Gbit but no
    > improvement. If I cannot figure this out then I will just attach it to
    > the Unix host with the other neo 2000, but its always nice to have more
    > options. I would not bother operating a LTO4 drive at such a slow speed
    > in production because shoe-shining would probably wear it out and the
    > compression would be sub optimal or non-existent.
    >
    > ------------------------------------------------------------------------
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