BACKUP to share over UNC path is very slow

  • Alex Webber (8/18/2011)


    How could user permissions have anything to do with it? Surely you either have the right permissions or you don't?

    Agreed. I don't see how permissions could play into the issue.

    And as for Instant File Initialisation, that's only for creating new data files (skipping the zero'ing phrase) so how does that come in to play?

    That setting doesn't affect backup files, only data files.

    The facts don't compute Alex, which probably why you posted. I'll step aside now 🙂

    There are no special teachers of virtue, because virtue is taught by the whole community.
    --Plato

  • Yeah, it's painful! Another point of note, the old server (1hr backup) was a Dell 515r and the new server (15hr backup) is a HP DL380 G7.

    So yeah I guess if anyone has had any pain from switching to Dell to HP then that might give me some pointers?

  • Also just to add for even more info, the major differences between the two are

    Dell

    Raid Controller: Perc(megaraid)

    NOC chipset: Broadcom

    CPU: AMD

    HP

    Raid Controller: LSI (variant)

    NOC chipset: Intel

    CPU: Intel

  • I'd expect the Dell raid controller to be better but the HP chipset and processor to be better or at least as good.

    I am scratching my head on this one.

    You said firewall was configured the same - does that include windows firewall on destination server?

    Jason...AKA CirqueDeSQLeil
    _______________________________________________
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  • Yup. tried with all firewalls disabled.

  • Another "out there" thought... Have you made sure that nothing else IO intensive is happening on the destination server when the UNC backup is run? Tried scheduling for a different time? I say this because I encountered a mysterious slowdown once that turned out to be Windows Shadow Copy consuming IO and diskspace in the background.

  • You said that you have HP server now. How many NICS does it have? How is it configured? Teaming or do you have a dedicated NIC for just File copy and one Public for SQL Server?

    -Roy

  • I hate to admit this, but if we need a bunch of scratch space on a disk and we can't do anything else, we just go buy a 500 gb portable USB drive, and attach to the server. This is pretty slow (compared to SaS), but it sure beats 15 hrs. We can usually do about a gb a minute. USB 3.0 is even faster, if the server can do it.

  • Had a similar issue at a previous employer, turned out the port on one of the switches was set to half-duplex. Just an idea.

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  • Lynn Pettis (8/23/2011)


    Had a similar issue at a previous employer, turned out the port on one of the switches was set to half-duplex. Just an idea.

    That was where my thoughts were turning too. I would check that the NICs are actually set to the same values and not relying on autoconfigure - especially after a change in hardware.

    But I agree that the practical solution is to provide some sort of local storage to hold a backup until you copy it to a network drive, for security or further backup to other medium.

  • Cheers for those responses guys. Our sys guys are currently looking at that so I'll feedback should they find anything!

  • Hi

    I know this is quite an old thread but may still be interesting.

    Have been struggling with net backups as well. Noticed CPU priv time% gradually going up while backup throughput doing down when backing up large database (300Gb). This only occurs on Win2003SP2/SQL 2005.

    After 2 days of investigating (robocopy, teracopy, unbuffered I/O stuff, SystemCacheDirtyPageThreshold registry setting...) I finally found this...

    http://connect.microsoft.com/SQLServer/feedback/details/286001/backing-up-to-network-unc-path-slows-down-over-time

    We're on SQL 2008R2 now and we don't have any problems. No idea what SP or hotfix the patch is included in though.

    Regards

    Thierry

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