Re: Does solaris require disks to be zeroed before using

From: Beardy (beardy_at_beardy.net)
Date: 09/25/04

  • Next message: Beardy: "Re: Does solaris require disks to be zeroed before using" 
    Date: Sat, 25 Sep 2004 06:10:28 +0000

    David A.Lethe wrote:
    > On Fri, 24 Sep 2004 21:22:49 +0000, Beardy <beardy@beardy.net> wrote:
    >
    >
    >>David A.Lethe wrote:
    >>
    >>>On 23 Sep 2004 22:31:46 GMT, Scott Howard <scott@hunterlink.net.au>
    >>>wrote:
    >>>
    >>>
    >>>
    >>>>David A.Lethe <davidATsantools.com> wrote:
    >>>>
    >>>>
    >>>>>This is causing some issues at our company, and we can't get any
    >>>>>definitive answers. Is there any requirement, or even best-practices
    >>>>>policies that SCSI and/or fibre channel disk drives need to have all
    >>>>>zeros written to them before partitioning and building a file system
    >>>>>on them?
    >>>>
    >>>>In a word, no.
    >>>>
    >>>>Solaris will never attempt to read a block of data which it hasn't
    >>>>previously written something to.
    >>>>
    >>>>Scott
    >>>
    >>>
    >>>Not true, and this explains the whole point of the question.
    >>>
    >>>Example .. .when you run the format command. Obviously it doesn't
    >>>write before reading, or every time you ran it, it would blow the
    >>>partitions away ;)
    >>
    >>OK format will check for the existence of a valid label on the disk
    >>first, and if not present, allow you to label the disk at that point.
    >>This is an exception, and I think the OP was referring to whether data
    >>blocks on disk should be zeroed, which they need not be; except in the
    >>unusual case that Casper referred to.
    >
    >
    > so data need not be zeroed except in unusual cases where it needs to
    > be zeroed?
    >
    > So Scott seems to be saying solaris does a read-before-write on a
    > block? That couldn't possibly be correct either.
    >
    >>>This brings up the reason for the question to begin with. The test
    >>>suites don't wipe the disks clean, and we had what might have been a
    >>>zillion-to-one shot where fdisk (on LINUX) exited with an invalid
    >>>partition error when the sysadmin tried to partition things.
    >>
    >>Your case is not relevant to the OP's question. The fact that the test
    >>suites may leave patterns on the disk is still not a problem. A random
    >>pattern and a regular pattern are identical if Solaris doesn't know they
    >>are there.
    >
    >
    >
    > As I am the OP, I think I have the right to decide what is relevent ;)
    > The test suites leaving info on the disks IS relevent. Does solaris
    > require, or is it even best practice to have a disk zeroed before
    > using it? I couldn't see anything online that said one way or
    > another, only that disks must be formatted before using.

    Yup. Apols David - my bad. I think that it really is comfort-factor for
    you. If you feel that zeroing the entire disk before use is the thing to
    do, then it will do no harm; just take potentially excessive time. In
    all my years working with Solaris GA and beta software (and for that
    matter, any other flavour of UNIX), I have never done this, and have
    never had a problem/panic which lent itself to suggest that patterned
    data in a disk sector was the root cause. Again, I cannot speak for
    Linux, but do suspect that your fdisk problem was the one in the
    haystack. I once had a colleague who said that disk failure were caused
    by "high-powered alpha particles ripping through the ionosphere" - could
    have been one of those.

    Apols again,

    Beardy.

  • Next message: Beardy: "Re: Does solaris require disks to be zeroed before using"

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