Re: taskqueue timeout - FreeBSD

This is a discussion on Re: taskqueue timeout - FreeBSD ; Matthew Dillon wrote: > Try that first. If it helps then it is a known issue. Basically > a combination of the on-disk write cache and possible ECC corrections, > remappings, or excessive remapped sectors can cause the drive to ...

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Thread: Re: taskqueue timeout

  1. Re: taskqueue timeout

    Matthew Dillon wrote:
    > Try that first. If it helps then it is a known issue. Basically
    > a combination of the on-disk write cache and possible ECC corrections,
    > remappings, or excessive remapped sectors can cause the drive to take
    > much longer then normal to complete a request. The default 5-second
    > timeout is insufficient.


    From Western Digital's line of "enterprise" drives:

    "RAID-specific time-limited error recovery (TLER) - Pioneered by WD,
    this feature prevents drive fallout caused by the extended hard drive
    error-recovery processes common to desktop drives."


    Western Digital's information sheet on TLER states that they found most
    RAID controllers will wait 8 seconds for a disk to respond before
    dropping it from the RAID set. Consequently they changed their
    "enterprise" drives to try reading a bad sector for only 7 seconds
    before returning an error.

    Therefore I think the FreeBSD timeout should also be set to 8 seconds
    instead of 5 seconds. Desktop-targetted drives will not respond for
    over 10 seconds, up to minutes, so its not worth setting the FreeBSD
    timeout any higher.


    More info:
    http://www.wdc.com/en/library/sata/2579-001098.pdf
    http://en.wikipedia.org/wiki/Time-Li...Error_Recovery



    - Andrew
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  2. Re: taskqueue timeout

    Andrew Snow wrote:

    > From Western Digital's line of "enterprise" drives:
    >
    > "RAID-specific time-limited error recovery (TLER) - Pioneered by WD,
    > this feature prevents drive fallout caused by the extended hard drive
    > error-recovery processes common to desktop drives."


    > Therefore I think the FreeBSD timeout should also be set to 8 seconds
    > instead of 5 seconds. Desktop-targetted drives will not respond for
    > over 10 seconds, up to minutes, so its not worth setting the FreeBSD
    > timeout any higher.


    Interesting you say this. To reiterate, I have /boot on USB thumb drive,
    and the system is mounted from / on a raidz pool called /storage via
    loader.conf.

    The four drives in question (per the packaging) are:

    - Western Digital Caviar SE16 500GB
    - 7200, 16MB, SATA-300, OEM

    Per the packaging on the rest of the hardware:

    # mobo
    - XFX 610i, 7050 GeForce (I *never* use graphics on my FreeBSD boxen, I
    *only* know/have CLI with no 'windows')

    # memory
    - 2 GB Corsair XMS2 Twin2X 6400C4 memory

    # cpu
    - Intel Pentium DC E2200 2.20GHz OEM
    - 2.20 GHz, 1MB Cache, 800MHz FSB, Allendale, Dual Core, OEM, Socket
    775, Processor

    # swap
    - I don't run any, but can/will add in an IDE/ATA 7200 200GB in the
    event this problem may be related to ZFS/RAM issues.

    Steve
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