Disk shadowing with bad blocks - VMS

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  1. Disk shadowing with bad blocks

    I have a disk that has some bad blocks.

    When I put it into a shadow set with a disk with no error, the disk
    with the bad blocks logs a few errors, but completes OK.

    When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    But, as far as I know, the shadow set is basically sound. I used this
    disk for months, I get no errors on image backup.

    Now, if I was not disk shadowing, I could just run the bad block
    finding command and then use the disk without any problems. Seems
    ironic.

    Is there a way to use this disk in a shadow set without getting these
    errors? Shadow sets seem to keep hitting the bad blocks.


  2. Re: Disk shadowing with bad blocks

    On Tue, 25 Mar 2008, tadamsmar wrote:

    > I have a disk that has some bad blocks.


    I don't understand why this disk *still* has bad blocks. The bad
    blocks should have all been replaced from the spare blocks by now,
    should they not? You have done ANALYZE/MEDIA/EXERCISE, haven't you?

    And if you are out of spare blocks, so that you have bad blocks
    existing, is the disk worth keeping? It must be on its last legs. It
    will certainly continue to grow bad blocks.

    Finally, my out-of-date "how shadowing works" information says that
    all the drives of the shadow set must have bad blocks at the same
    locations. If this restriction exists for you, then you will either
    have to give up on the drive, or add bad blocks to the other drives of
    the shadow set.


    --

    Rob Brown b r o w n a t g m c l d o t c o m
    G. Michaels Consulting Ltd. (780)438-9343 (voice)
    Edmonton (780)437-3367 (FAX)
    http://gmcl.com/


  3. Re: Disk shadowing with bad blocks

    On Tue, 25 Mar 2008 10:06:43 -0700 (PDT), tadamsmar
    wrote:

    >I have a disk that has some bad blocks.
    >
    >When I put it into a shadow set with a disk with no error, the disk
    >with the bad blocks logs a few errors, but completes OK.
    >
    >When I do a ANAL/DISK/SHAD, the command ends with a parity error.
    >
    >But, as far as I know, the shadow set is basically sound. I used this
    >disk for months, I get no errors on image backup.
    >
    >Now, if I was not disk shadowing, I could just run the bad block
    >finding command and then use the disk without any problems. Seems
    >ironic.
    >
    >Is there a way to use this disk in a shadow set without getting these
    >errors? Shadow sets seem to keep hitting the bad blocks.


    Have you logged a service call ? I think if the errorlog, VMS
    versions/patch level, log from the ana/disk/shadow, and the hardware
    details were included you would get a quicker answer.

    Pete

  4. Re: Disk shadowing with bad blocks

    tadamsmar wrote:
    >
    > I have a disk that has some bad blocks.
    >
    > When I put it into a shadow set with a disk with no error, the disk
    > with the bad blocks logs a few errors, but completes OK.
    >
    > When I do a ANAL/DISK/SHAD, the command ends with a parity error.
    >
    > But, as far as I know, the shadow set is basically sound. I used this
    > disk for months, I get no errors on image backup.
    >
    > Now, if I was not disk shadowing, I could just run the bad block
    > finding command and then use the disk without any problems. Seems
    > ironic.
    >
    > Is there a way to use this disk in a shadow set without getting these
    > errors? Shadow sets seem to keep hitting the bad blocks.


    After everything in the previous thread, it seems there really only two
    things left to try:

    1. INIT/ERASE
    2. Low-level format
    3. A dangerously high precipice

    David J Dachtera
    (formerly dba) DJE Systems

  5. Re: Disk shadowing with bad blocks

    On Mar 25, 8:05*pm, David J Dachtera
    wrote:
    > tadamsmar wrote:
    >
    > > I have a disk that has some bad blocks.

    >
    > > When I put it into a shadow set with a disk with no error, the disk
    > > with the bad blocks logs a few errors, but completes OK.

    >
    > > When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    >
    > > But, as far as I know, the shadow set is basically sound. *I used this
    > > disk for months, I get no errors on image backup.

    >
    > > Now, if I was not disk shadowing, I could just run the bad block
    > > finding command and then use the disk without any problems. *Seems
    > > ironic.

    >
    > > Is there a way to use this disk in a shadow set without getting these
    > > errors? * Shadow sets seem to keep hitting the bad blocks.

    >
    > After everything in the previous thread, it seems there really only two
    > things left to try:
    >
    > 1. INIT/ERASE
    > 2. Low-level format
    > 3. A dangerously high precipice
    >
    > David J Dachtera
    > (formerly dba) DJE Systems- Hide quoted text -
    >
    > - Show quoted text -


    I don't think I am communicating very well at this point.

    My system works fine if I use only good disks that have no bad
    physical blocks.

    But I now have one spare disk with some bad physical blocks. It
    setting in my office not installed. I tried to use it and this
    happened:

    1. It logged errors during the shadow copy to it from a perfectly
    good disk. But the copy worked.

    2. After the copy, ANAL/DISK/SHAD ends with a parity error.

    Now, I am thinking about keeping this disk as a spare since is sort of
    works in a shadow set. But I was wondering if there was as way to
    avoid having these spurious errors reported. Disk shadowing seems to
    have no way to stop reporting over and over the bad blocks on this
    disks.

  6. Re: Disk shadowing with bad blocks

    On Mar 26, 7:52 am, tadamsmar wrote:
    > On Mar 25, 8:05 pm, David J Dachtera
    > wrote:
    >
    >
    >
    > > tadamsmar wrote:

    >
    > > > I have a disk that has some bad blocks.

    >
    > > > When I put it into a shadow set with a disk with no error, the disk
    > > > with the bad blocks logs a few errors, but completes OK.

    >
    > > > When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    >
    > > > But, as far as I know, the shadow set is basically sound. I used this
    > > > disk for months, I get no errors on image backup.

    >
    > > > Now, if I was not disk shadowing, I could just run the bad block
    > > > finding command and then use the disk without any problems. Seems
    > > > ironic.

    >
    > > > Is there a way to use this disk in a shadow set without getting these
    > > > errors? Shadow sets seem to keep hitting the bad blocks.

    >
    > > After everything in the previous thread, it seems there really only two
    > > things left to try:

    >
    > > 1. INIT/ERASE
    > > 2. Low-level format
    > > 3. A dangerously high precipice

    >
    > > David J Dachtera
    > > (formerly dba) DJE Systems- Hide quoted text -

    >
    > > - Show quoted text -

    >
    > I don't think I am communicating very well at this point.
    >
    > My system works fine if I use only good disks that have no bad
    > physical blocks.
    >
    > But I now have one spare disk with some bad physical blocks. It
    > setting in my office not installed. I tried to use it and this
    > happened:
    >
    > 1. It logged errors during the shadow copy to it from a perfectly
    > good disk. But the copy worked.
    >
    > 2. After the copy, ANAL/DISK/SHAD ends with a parity error.
    >
    > Now, I am thinking about keeping this disk as a spare since is sort of
    > works in a shadow set. But I was wondering if there was as way to
    > avoid having these spurious errors reported. Disk shadowing seems to
    > have no way to stop reporting over and over the bad blocks on this
    > disks.


    Get another disk already. This is the second thread about this
    problem, no?

    AEF

  7. Re: Disk shadowing with bad blocks

    On Mar 25, 7:39*pm, Rob Brown wrote:
    > On Tue, 25 Mar 2008, tadamsmar wrote:
    > > I have a disk that has some bad blocks.

    >
    > I don't understand why this disk *still* has bad blocks. *The bad
    > blocks should have all been replaced from the spare blocks by now,
    > should they not? *You have done ANALYZE/MEDIA/EXERCISE, haven't you?


    Yes, it finds some bad blocks and put their addresses in the bad block
    file, but that file is wiped out when you put a disk in a shadow set.
    You are mixing the non-shadow and shadow algorithms for addressing bad
    blocks. ANAL/MEDIS/EXER is a tool handling bad blocks when you are not
    shadowing.

    >
    > And if you are out of spare blocks, so that you have bad blocks
    > existing, is the disk worth keeping? *It must be on its last legs. *It
    > will certainly continue to grow bad blocks.


    I have plenty of spares. Not the problem.

    >
    > Finally, my out-of-date "how shadowing works" information says that
    > all the drives of the shadow set must have bad blocks at the same
    > locations. *If this restriction exists for you, then you will either
    > have to give up on the drive, or add bad blocks to the other drives of
    > the shadow set.


    The bad blocks are not causing any real integrity problems, just
    spurious error reports.

    >
    > --
    >
    > Rob Brown * * * * * * * * * * * *b r o w n a t g mc l d o t c o m
    > G. Michaels Consulting Ltd. * * *(780)438-9343 (voice)
    > Edmonton * * * * * * * * * * * * (780)437-3367 (FAX)
    > * * * * * * * * * * * * * * * * *http://gmcl.com/



  8. Re: Disk shadowing with bad blocks

    On Mar 25, 7:54*pm, Pete wrote:
    > On Tue, 25 Mar 2008 10:06:43 -0700 (PDT), tadamsmar
    >
    >
    >
    >
    >
    > wrote:
    > >I have a disk that has some bad blocks.

    >
    > >When I put it into a shadow set with a disk with no error, the disk
    > >with the bad blocks logs a few errors, but completes OK.

    >
    > >When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    >
    > >But, as far as I know, the shadow set is basically sound. *I used this
    > >disk for months, I get no errors on image backup.

    >
    > >Now, if I was not disk shadowing, I could just run the bad block
    > >finding command and then use the disk without any problems. *Seems
    > >ironic.

    >
    > >Is there a way to use this disk in a shadow set without getting these
    > >errors? * Shadow sets seem to keep hitting the bad blocks.

    >
    > *Have you logged a service call ? I think if the errorlog, VMS
    > versions/patch level, log from the ana/disk/shadow, and the hardware
    > details were included you would get a quicker answer.
    >
    > Pete- Hide quoted text -
    >
    > - Show quoted text -


    I don't have a service contract, and the problem is not that critical.

  9. Re: Disk shadowing with bad blocks

    On Mar 26, 7:55*am, AEF wrote:
    > On Mar 26, 7:52 am, tadamsmar wrote:
    >
    >
    >
    >
    >
    > > On Mar 25, 8:05 pm, David J Dachtera
    > > wrote:

    >
    > > > tadamsmar wrote:

    >
    > > > > I have a disk that has some bad blocks.

    >
    > > > > When I put it into a shadow set with a disk with no error, the disk
    > > > > with the bad blocks logs a few errors, but completes OK.

    >
    > > > > When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    >
    > > > > But, as far as I know, the shadow set is basically sound. *I used this
    > > > > disk for months, I get no errors on image backup.

    >
    > > > > Now, if I was not disk shadowing, I could just run the bad block
    > > > > finding command and then use the disk without any problems. *Seems
    > > > > ironic.

    >
    > > > > Is there a way to use this disk in a shadow set without getting these
    > > > > errors? * Shadow sets seem to keep hitting the bad blocks.

    >
    > > > After everything in the previous thread, it seems there really only two
    > > > things left to try:

    >
    > > > 1. INIT/ERASE
    > > > 2. Low-level format
    > > > 3. A dangerously high precipice

    >
    > > > David J Dachtera
    > > > (formerly dba) DJE Systems- Hide quoted text -

    >
    > > > - Show quoted text -

    >
    > > I don't think I am communicating very well at this point.

    >
    > > My system works fine if I use only good disks that have no bad
    > > physical blocks.

    >
    > > But I now have one spare disk with some bad physical blocks. It
    > > setting in my office not installed. *I tried to use it and this
    > > happened:

    >
    > > 1. *It logged errors during the shadow copy to it from a perfectly
    > > good disk. *But the copy worked.

    >
    > > 2. *After the copy, ANAL/DISK/SHAD ends with a parity error.

    >
    > > Now, I am thinking about keeping this disk as a spare since is sort of
    > > works in a shadow set. * But I was wondering if there was as way to
    > > avoid having these spurious errors reported. * Disk shadowing seems to
    > > have no way to stop reporting over and over the bad blocks on this
    > > disks.

    >
    > Get another disk already. This is the second thread about this
    > problem, no?
    >
    > AEF- Hide quoted text -
    >
    > - Show quoted text -


    I already have another disk.

    Just trying to figure out the usefulness of a disk that has a few bad
    blocks as a shadow set member.

    Actually, its the third thread.

  10. Re: Disk shadowing with bad blocks

    tadamsmar wrote:

    > [...big snip...]


    Please bite the bullet and do a low-level format
    of the disk (this will revector any genuine bad
    blocks, leaving you (hopefully) with a disk that
    has no bad blocks visible).

    Assuming disk is DKA400:

    $ mcr sys$etc:rztools_alpha
    RZTools> /h
    RZT [device] [/command[=value] /...]

    Commands Value required? Function
    -------- --------------- --------
    [...snip...]

    FO rmat SCSI FORMAT


    RZTools> DKA400:/Format

    And with that, hopefully this thread might come to an end.

  11. Re: Disk shadowing with bad blocks

    tadamsmar wrote:
    > On Mar 25, 8:05 pm, David J Dachtera
    > wrote:
    >
    >>tadamsmar wrote:
    >>
    >>
    >>>I have a disk that has some bad blocks.

    >>
    >>>When I put it into a shadow set with a disk with no error, the disk
    >>>with the bad blocks logs a few errors, but completes OK.

    >>
    >>>When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    >>
    >>>But, as far as I know, the shadow set is basically sound. I used this
    >>>disk for months, I get no errors on image backup.

    >>
    >>>Now, if I was not disk shadowing, I could just run the bad block
    >>>finding command and then use the disk without any problems. Seems
    >>>ironic.

    >>
    >>>Is there a way to use this disk in a shadow set without getting these
    >>>errors? Shadow sets seem to keep hitting the bad blocks.

    >>
    >>After everything in the previous thread, it seems there really only two
    >>things left to try:
    >>
    >>1. INIT/ERASE
    >>2. Low-level format
    >>3. A dangerously high precipice
    >>
    >>David J Dachtera
    >>(formerly dba) DJE Systems- Hide quoted text -
    >>
    >>- Show quoted text -

    >
    >
    > I don't think I am communicating very well at this point.
    >
    > My system works fine if I use only good disks that have no bad
    > physical blocks.
    >
    > But I now have one spare disk with some bad physical blocks. It
    > setting in my office not installed. I tried to use it and this
    > happened:
    >
    > 1. It logged errors during the shadow copy to it from a perfectly
    > good disk. But the copy worked.
    >
    > 2. After the copy, ANAL/DISK/SHAD ends with a parity error.
    >
    > Now, I am thinking about keeping this disk as a spare since is sort of
    > works in a shadow set. But I was wondering if there was as way to
    > avoid having these spurious errors reported. Disk shadowing seems to
    > have no way to stop reporting over and over the bad blocks on this
    > disks.


    I would retire that disk drive to a non critical position; e.g. a
    paperweight!

    YMMV!


  12. Re: Disk shadowing with bad blocks

    On Mar 26, 9:11*am, "Richard B. Gilbert"
    wrote:
    > tadamsmar wrote:
    > > On Mar 25, 8:05 pm, David J Dachtera
    > > wrote:

    >
    > >>tadamsmar wrote:

    >
    > >>>I have a disk that has some bad blocks.

    >
    > >>>When I put it into a shadow set with a disk with no error, the disk
    > >>>with the bad blocks logs a few errors, but completes OK.

    >
    > >>>When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    >
    > >>>But, as far as I know, the shadow set is basically sound. *I used this
    > >>>disk for months, I get no errors on image backup.

    >
    > >>>Now, if I was not disk shadowing, I could just run the bad block
    > >>>finding command and then use the disk without any problems. *Seems
    > >>>ironic.

    >
    > >>>Is there a way to use this disk in a shadow set without getting these
    > >>>errors? * Shadow sets seem to keep hitting the bad blocks.

    >
    > >>After everything in the previous thread, it seems there really only two
    > >>things left to try:

    >
    > >>1. INIT/ERASE
    > >>2. Low-level format
    > >>3. A dangerously high precipice

    >
    > >>David J Dachtera
    > >>(formerly dba) DJE Systems- Hide quoted text -

    >
    > >>- Show quoted text -

    >
    > > I don't think I am communicating very well at this point.

    >
    > > My system works fine if I use only good disks that have no bad
    > > physical blocks.

    >
    > > But I now have one spare disk with some bad physical blocks. It
    > > setting in my office not installed. *I tried to use it and this
    > > happened:

    >
    > > 1. *It logged errors during the shadow copy to it from a perfectly
    > > good disk. *But the copy worked.

    >
    > > 2. *After the copy, ANAL/DISK/SHAD ends with a parity error.

    >
    > > Now, I am thinking about keeping this disk as a spare since is sort of
    > > works in a shadow set. * But I was wondering if there was as way to
    > > avoid having these spurious errors reported. * Disk shadowing seems to
    > > have no way to stop reporting over and over the bad blocks on this
    > > disks.

    >
    > I would retire that disk drive to a non critical position; e.g. a
    > paperweight!
    >
    > YMMV!- Hide quoted text -
    >
    > - Show quoted text -


    I am thinking about keeping it as a backup. If I lost a disk, then I
    could use it as a temporary replacement till I ordered a new disk. It
    works fine in a shadow set if you understand the "features" of disk
    shadowing. The main problem is that you have to sort out real from
    spurious error reports and the spurious parity errors will be
    propagated to other disks after you allow the problem disk to be the
    only member of a shadow set. In that case, you have to go to the
    trouble of wiping out the spurious parity errors.

    Could be a paperweight in the meantime if I keep it its anti-static
    bag.

  13. Re: Disk shadowing with bad blocks

    On Wed, 26 Mar 2008, tadamsmar wrote:

    > On Mar 25, 7:39 pm, Rob Brown wrote:
    >>
    >> And if you are out of spare blocks, so that you have bad blocks
    >> existing, is the disk worth keeping? It must be on its last legs. It
    >> will certainly continue to grow bad blocks.

    >
    > I have plenty of spares. Not the problem.


    Obviously you do not have spares, since you have bad blocks.

    If you had spare blocks, as soon as you wrote to a bad block, it would
    have been replaced with a good spare block with the same LBN. The
    host would never know about it. And this happens below the level of
    BADBLOCK.SYS, which the host maintains.

    >> Finally, my out-of-date "how shadowing works" information says that
    >> all the drives of the shadow set must have bad blocks at the same
    >> locations. If this restriction exists for you, then you will either
    >> have to give up on the drive, or add bad blocks to the other drives of
    >> the shadow set.


    > The bad blocks are not causing any real integrity problems,


    ;-) What kind of integrity problems is it causing then? ;-)

    Seriously, if you have data shadowed to a bad block, then you do not
    have that data shadowed.

    > just spurious error reports.


    Then add the bad blocks to the the bad block list on both drives, and
    then you won't get the error reports.

    - Rob


    --

    Rob Brown b r o w n a t g m c l d o t c o m
    G. Michaels Consulting Ltd. (780)438-9343 (voice)
    Edmonton (780)437-3367 (FAX)
    http://gmcl.com/


  14. Re: Disk shadowing with bad blocks

    On Mar 26, 10:19 am, tadamsmar wrote:
    > On Mar 26, 9:11 am, "Richard B. Gilbert"
    > wrote:
    >
    >
    >
    > > tadamsmar wrote:
    > > > On Mar 25, 8:05 pm, David J Dachtera
    > > > wrote:

    >
    > > >>tadamsmar wrote:

    >
    > > >>>I have a disk that has some bad blocks.

    >
    > > >>>When I put it into a shadow set with a disk with no error, the disk
    > > >>>with the bad blocks logs a few errors, but completes OK.

    >
    > > >>>When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    >
    > > >>>But, as far as I know, the shadow set is basically sound. I used this
    > > >>>disk for months, I get no errors on image backup.

    >
    > > >>>Now, if I was not disk shadowing, I could just run the bad block
    > > >>>finding command and then use the disk without any problems. Seems
    > > >>>ironic.

    >
    > > >>>Is there a way to use this disk in a shadow set without getting these
    > > >>>errors? Shadow sets seem to keep hitting the bad blocks.

    >
    > > >>After everything in the previous thread, it seems there really only two
    > > >>things left to try:

    >
    > > >>1. INIT/ERASE
    > > >>2. Low-level format
    > > >>3. A dangerously high precipice

    >
    > > >>David J Dachtera
    > > >>(formerly dba) DJE Systems- Hide quoted text -

    >
    > > >>- Show quoted text -

    >
    > > > I don't think I am communicating very well at this point.

    >
    > > > My system works fine if I use only good disks that have no bad
    > > > physical blocks.

    >
    > > > But I now have one spare disk with some bad physical blocks. It
    > > > setting in my office not installed. I tried to use it and this
    > > > happened:

    >
    > > > 1. It logged errors during the shadow copy to it from a perfectly
    > > > good disk. But the copy worked.

    >
    > > > 2. After the copy, ANAL/DISK/SHAD ends with a parity error.

    >
    > > > Now, I am thinking about keeping this disk as a spare since is sort of
    > > > works in a shadow set. But I was wondering if there was as way to
    > > > avoid having these spurious errors reported. Disk shadowing seems to
    > > > have no way to stop reporting over and over the bad blocks on this
    > > > disks.

    >
    > > I would retire that disk drive to a non critical position; e.g. a
    > > paperweight!

    >
    > > YMMV!- Hide quoted text -

    >
    > > - Show quoted text -

    >
    > I am thinking about keeping it as a backup. If I lost a disk, then I
    > could use it as a temporary replacement till I ordered a new disk. It
    > works fine in a shadow set if you understand the "features" of disk
    > shadowing. The main problem is that you have to sort out real from
    > spurious error reports and the spurious parity errors will be
    > propagated to other disks after you allow the problem disk to be the
    > only member of a shadow set. In that case, you have to go to the
    > trouble of wiping out the spurious parity errors.
    >
    > Could be a paperweight in the meantime if I keep it its anti-static
    > bag.


    Are you bored?

    AEf

  15. Re: Disk shadowing with bad blocks

    On Tue, 25 Mar 2008, Rob Brown wrote:

    > You have done ANALYZE/MEDIA/EXERCISE, haven't you?


    Perhaps this should have been ANALYZE/MEDIA/EXERCISE/RETRY.


    --

    Rob Brown b r o w n a t g m c l d o t c o m
    G. Michaels Consulting Ltd. (780)438-9343 (voice)
    Edmonton (780)437-3367 (FAX)
    http://gmcl.com/


  16. Re: Disk shadowing with bad blocks

    On Mar 26, 11:54*am, Rob Brown wrote:
    > On Wed, 26 Mar 2008, tadamsmar wrote:
    > > On Mar 25, 7:39 pm, Rob Brown wrote:

    >
    > >> And if you are out of spare blocks, so that you have bad blocks
    > >> existing, is the disk worth keeping? *It must be on its last legs. *It
    > >> will certainly continue to grow bad blocks.

    >
    > > I have plenty of spares. *Not the problem.

    >
    > Obviously you do not have spares, since you have bad blocks.
    >
    > If you had spare blocks, as soon as you wrote to a bad block, it would
    > have been replaced with a good spare block with the same LBN. *The
    > host would never know about it. *And this happens below the level of
    > BADBLOCK.SYS, which the host maintains.


    It does replace the bad blocks. But it still reports the errors.

    Part of the problem is that disk shadowing reads in big chunks past
    the end of the files and can hit bad blocks in unused space. So, you
    don't have a real integrity issue with your shadow set, just spurious
    parity errors.

    >
    > >> Finally, my out-of-date "how shadowing works" information says that
    > >> all the drives of the shadow set must have bad blocks at the same
    > >> locations. *If this restriction exists for you, then you will either
    > >> have to give up on the drive, or add bad blocks to the other drives of
    > >> the shadow set.

    > > The bad blocks are not causing any real integrity problems,

    >
    > ;-) What kind of integrity problems is it causing then? *;-)


    1. Errors logged during shadow copy
    2. ANAL/DISK/SHAD ends with a parity error
    3. If you reduce the shadow set to the one disk with the bad blocks,
    then spurious parity errors are propagated to any disk you add to the
    shadow set.

    The parity errors are past the end of files not really inside files.
    This is a "feature" of VMS disk shadowing, it reports some errors that
    are not really in files. ANAL/DISK/SHAD fails on these errors.

    Read the recent threads on this. That's how I learned about this
    "feature".

    >
    > Seriously, if you have data shadowed to a bad block, then you do not
    > have that data shadowed.
    >
    > > just spurious error reports.

    >
    > Then add the bad blocks to the the bad block list on both drives, and
    > then you won't get the error reports.
    >
    > - Rob
    >
    > --
    >
    > Rob Brown * * * * * * * * * * * *b r o w n a t g mc l d o t c o m
    > G. Michaels Consulting Ltd. * * *(780)438-9343 (voice)
    > Edmonton * * * * * * * * * * * * (780)437-3367 (FAX)
    > * * * * * * * * * * * * * * * * *http://gmcl.com/



  17. Re: Disk shadowing with bad blocks

    On Mar 26, 8:15*am, "R.A.Omond" wrote:
    > tadamsmar wrote:
    > > [...big snip...]

    >
    > Please bite the bullet and do a low-level format
    > of the disk (this will revector any genuine bad
    > blocks, leaving you (hopefully) with a disk that
    > has no bad blocks visible).
    >
    > Assuming disk is DKA400:
    >
    > $ mcr sys$etc:rztools_alpha
    > RZTools> /h
    > * *RZT [device] [/command[=value] /...]
    >
    > * *Commands * Value required? *Function
    > * *-------- * --------------- *--------
    > * [...snip...]
    >
    > * *FO rmat * * * * * * * * * * SCSI FORMAT
    >
    > RZTools> DKA400:/Format
    >
    > And with that, hopefully this thread might come to an end.


    Thanks!

    The End

    (except poor, confused Rob Brown might keep posting)

  18. Re: Disk shadowing with bad blocks


    On Wed, 26 Mar 2008 05:01:40 -0700 (PDT), tadamsmar
    wrote:

    >On Mar 25, 7:54*pm, Pete wrote:
    >> On Tue, 25 Mar 2008 10:06:43 -0700 (PDT), tadamsmar
    >>
    >>
    >>
    >>
    >>
    >> wrote:
    >> >I have a disk that has some bad blocks.

    >>
    >> >When I put it into a shadow set with a disk with no error, the disk
    >> >with the bad blocks logs a few errors, but completes OK.

    >>
    >> >When I do a ANAL/DISK/SHAD, the command ends with a parity error.

    >>
    >> >But, as far as I know, the shadow set is basically sound. *I used this
    >> >disk for months, I get no errors on image backup.

    >>
    >> >Now, if I was not disk shadowing, I could just run the bad block
    >> >finding command and then use the disk without any problems. *Seems
    >> >ironic.

    >>
    >> >Is there a way to use this disk in a shadow set without getting these
    >> >errors? * Shadow sets seem to keep hitting the bad blocks.

    >>
    >> *Have you logged a service call ? I think if the errorlog, VMS
    >> versions/patch level, log from the ana/disk/shadow, and the hardware
    >> details were included you would get a quicker answer.
    >>
    >> Pete- Hide quoted text -
    >>
    >> - Show quoted text -

    >
    >I don't have a service contract, and the problem is not that critical.


    Try a low level format (as someone already suggested). If you working
    with an unsupported disk I would check/read up on AWRE and ARRE bits
    on the drive. Might be automatic replacement is disabled. While you're
    reading that you should come across the grown defect list have a look
    at that. Manual for the drive should be available from the
    manufacturer.

    Pete


  19. Re: Disk shadowing with bad blocks

    tadamsmar writes:

    >Yes, it finds some bad blocks and put their addresses in the bad block
    >file, but that file is wiped out when you put a disk in a shadow set.
    >You are mixing the non-shadow and shadow algorithms for addressing bad
    >blocks. ANAL/MEDIS/EXER is a tool handling bad blocks when you are not
    >shadowing.


    It will tell you if the blocks are actually bad, and from what you
    write, they really are. I wouldn't add it to your shadowset. Right now
    it appears none of the bad blocks land in a file when you do, but why take
    the chance? You don't know for certain whether the drive is dying.

    I would either:

    1) Run ANALYZE/MED/EXER/RETRY and have it update the bad block file and
    then use the drive for data you don't care about
    2) Low level format it (unsupported tool to do so in SYS$ETC and see
    if it gets better (run ANALYZE/MED/EXER after)
    3) Attach a chain to it, and use to keep a small boat in place

    in reverse order of preference.

    You could add the blocks to the shadowset's bad block file, but why?

  20. Re: Disk shadowing with bad blocks

    On Mar 26, 2:28*pm, moro...@world.std.spaamtrap.com (Michael Moroney)
    wrote:
    > tadamsmar writes:
    > >Yes, it finds some bad blocks and put their addresses in the bad block
    > >file, but that file is wiped out when you put a disk in a shadow set.
    > >You are mixing the non-shadow and shadow algorithms for addressing bad
    > >blocks. ANAL/MEDIS/EXER is a tool handling bad blocks when you are not
    > >shadowing.

    >
    > It will tell you if the blocks are actually bad, and from what you
    > write, they really are. *I wouldn't add it to your shadowset. *Right now
    > it appears none of the bad blocks land in a file when you do, but why take
    > the chance?


    Why? Because the chance is zero+nada*nothing**2

    > You don't know for certain whether the drive is dying.
    >
    > I would either:
    >
    > 1) Run ANALYZE/MED/EXER/RETRY and have it update the bad block file and
    > * *then use the drive for data you don't care about
    > 2) Low level format it (unsupported tool to do so in SYS$ETC and see
    > * *if it gets better (run ANALYZE/MED/EXER after)
    > 3) Attach a chain to it, and use to keep a small boat in place
    >
    > in reverse order of preference.
    >
    > You could add the blocks to the shadowset's bad block file, but why?



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