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sbp, camcontrol, and Tagged Queuing - FreeBSD

I posted this a while back and am still having the same problem. Can anyone offer any insight as to if the sbp man page suggestion about tagged queuing is something I should try? Is there any risk of ing up my drives by trying this? Thanks, Drew -------- Original Message -------- Subject: Help Interpreting sbp0 Errors Date: Mon, 24 Jan 2005 11:43:21 -0800 From: Drew Tomlinson <net> I've been having problems with vinum volumes since an upgrade from 4.9 to 4.10 which I posted about here: http://docs.freebsd.org/cgi/mid.cgi?41D748F0.1000303 However maybe that is the *symptom* instead of the *problem*. I shut ...

  1. #1

    Default sbp, camcontrol, and Tagged Queuing

    I posted this a while back and am still having the same problem. Can anyone
    offer any insight as to if the sbp man page suggestion about tagged queuing
    is something I should try? Is there any risk of ing up my drives by
    trying this?

    Thanks,

    Drew

    -------- Original Message --------
    Subject: Help Interpreting sbp0 Errors
    Date: Mon, 24 Jan 2005 11:43:21 -0800
    From: Drew Tomlinson <net>

    I've been having problems with vinum volumes since an upgrade from 4.9
    to 4.10 which I posted about here:

    http://docs.freebsd.org/cgi/mid.cgi?41D748F0.1000303

    However maybe that is the *symptom* instead of the *problem*. I shut
    down my system from the console and saw this output:

    --- BEGIN ---
    boot() called on cpu#0
    Waiting (max 60 seconds) for system process `vnlru' to stop...stopped
    Waiting (max 60 seconds) for system process `bufdaemon' to stop...stopped
    Waiting (max 60 seconds) for system process `syncer' to stop...stopped

    syncing disks... 4
    done
    Uptime: 28d20h48m39s
    sbp0:0:0 request timeout(mgm orb:0x0a550b14) ... reset start
    sbp0:0:0 request timeout(cmd orb:0x0a550c4c) ... agent reset
    (da2:sbp0:0:0:0): Synchronize cache failed, status == 0xb, scsi status
    == 0x0
    sbp0:0:1 request timeout(cmd orb:0x0a5528a4) ... agent reset
    (da3:sbp0:0:0:1): Synchronize cache failed, status == 0xb, scsi status
    == 0x0

    The operating system has halted.
    Please press any key to reboot.
    --- END ---

    da2 and da3 are two IDE drives in a firewire enclosure. These are also
    the drives that come up "referenced" after restarting. What do these
    errors mean? How can I correct them? Is the following section from the
    sbp man page applicable to my situation?

    Some (broken) HDDs don't work well with tagged queuing. If you have prob-
    lems with such drives, try ``camcontrol [device id] tags -N 1'' to dis-
    able tagged queuing.

    Thanks for your help!

    Drew

    Drew Guest

  2. #2

    Default Re: sbp, camcontrol, and Tagged Queuing

    On Thursday 17 March 2005 10:08 pm, Drew Tomlinson wrote: 

    Tagged queueing queues up multiple instructions for the drive simultaneously.
    The drive then attempts to sort them out and execute them in optimum order.
    Some drives that claim to support tagged queueing do not correctly do so, and
    don't perform well when it is used (and may lose data). If you set the queue
    size to one, as recommended in the passage you reference, then only one
    instruction will be issued to the drive at time, and it will behave like a
    drive without tagged queueing. It will do no harm to the drive. If the
    drive correctly implements tagged queueing, this will slow down the drive,
    but if it does not correctly implement it, then this may dramatically speed
    up the drive (and make it more stable). I have an external drive that
    manages 1.3 MBps transfers with queueing enabled, and 25 MBps transfers when
    I set the queue size to one.

    As for whether it will help your specific problem, I don't know, but I can't
    see how it would do any harm to test it.

    This issue is not specific to FreeBSD. Any OS that supports tagged queuing
    has problems with some drives.

    - Bob

     

    [...]
     
    Bob Guest

  3. #3

    Default Re: sbp, camcontrol, and Tagged Queuing

    On 3/17/2005 8:23 PM Bob Johnson wrote:
     
    >Tagged queueing queues up multiple instructions for the drive simultaneously.
    >The drive then attempts to sort them out and execute them in optimum order.
    >Some drives that claim to support tagged queueing do not correctly do so, and
    >don't perform well when it is used (and may lose data). If you set the queue
    >size to one, as recommended in the passage you reference, then only one
    >instruction will be issued to the drive at time, and it will behave like a
    >drive without tagged queueing. It will do no harm to the drive. If the
    >drive correctly implements tagged queueing, this will slow down the drive,
    >but if it does not correctly implement it, then this may dramatically speed
    >up the drive (and make it more stable). I have an external drive that
    >manages 1.3 MBps transfers with queueing enabled, and 25 MBps transfers when
    >I set the queue size to one.
    >
    >As for whether it will help your specific problem, I don't know, but I can't
    >see how it would do any harm to test it.
    >
    >This issue is not specific to FreeBSD. Any OS that supports tagged queuing
    >has problems with some drives.
    >
    >- Bob
    >
    >[/ref]
    Thank you for your explanation. I will try this later today when I am
    close to the console and post my results for anyone else that may
    experience this problem.

    Cheers,

    Drew
     [/ref]
    Drew Guest

  4. #4

    Default Re: sbp, camcontrol, and Tagged Queuing

    On 3/17/2005 8:23 PM Bob Johnson wrote:
     
    >Tagged queueing queues up multiple instructions for the drive simultaneously.
    >The drive then attempts to sort them out and execute them in optimum order.
    >Some drives that claim to support tagged queueing do not correctly do so, and
    >don't perform well when it is used (and may lose data). If you set the queue
    >size to one, as recommended in the passage you reference, then only one
    >instruction will be issued to the drive at time, and it will behave like a
    >drive without tagged queueing. It will do no harm to the drive. If the
    >drive correctly implements tagged queueing, this will slow down the drive,
    >but if it does not correctly implement it, then this may dramatically speed
    >up the drive (and make it more stable). I have an external drive that
    >manages 1.3 MBps transfers with queueing enabled, and 25 MBps transfers when
    >I set the queue size to one.
    >
    >As for whether it will help your specific problem, I don't know, but I can't
    >see how it would do any harm to test it.
    >
    >[/ref]
    Using the camcontrol utility, I found these drives were already set to "1"

    blacklamb# camcontrol tags da2 -v
    (pass3:sbp0:0:0:0): dev_openings 1
    (pass3:sbp0:0:0:0): dev_active 0
    (pass3:sbp0:0:0:0): devq_openings 1
    (pass3:sbp0:0:0:0): devq_queued 0
    (pass3:sbp0:0:0:0): held 0
    (pass3:sbp0:0:0:0): mintags 2
    (pass3:sbp0:0:0:0): maxtags 255

    blacklamb# camcontrol tags da3 -v
    (pass4:sbp0:0:0:1): dev_openings 1
    (pass4:sbp0:0:0:1): dev_active 0
    (pass4:sbp0:0:0:1): devq_openings 1
    (pass4:sbp0:0:0:1): devq_queued 0
    (pass4:sbp0:0:0:1): held 0
    (pass4:sbp0:0:0:1): mintags 2
    (pass4:sbp0:0:0:1): maxtags 255

    Thus setting tagged queuing to "1" had no effect. Thanks again for your
    explanation. I sure wish I could solve this issue!

    Thanks,

    Drew
     
    >[/ref]
    Drew Guest

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