Meaning of Cyclic Redundancy Check Error? - Veritas Backup Exec

This is a discussion on Meaning of Cyclic Redundancy Check Error? - Veritas Backup Exec ; Hi, Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571. The daily backup failed last night and turns out there was a Cyclic Redundancy Check data error in the log during the VERIFY. I found TechNote ID: 192216 ...

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Thread: Meaning of Cyclic Redundancy Check Error?

  1. Meaning of Cyclic Redundancy Check Error?

    Hi,

    Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571. The
    daily backup failed last night and turns out there was a Cyclic
    Redundancy Check data error in the log during the VERIFY. I found
    TechNote ID: 192216 but it doesn't explain what the error means just
    possible causes. I did a test restore of a sampling of files and the
    restore went OKAY so I don't know if I can rely on the tape or not.
    Could someone shed some light on this?

    Regards,
    Dan

  2. Re: Meaning of Cyclic Redundancy Check Error?

    A CRC is a checksum calculated from the contents of the data for which it
    verifies integrity. BE does a read on the tape after b/u (unless you turn
    this off...would be very stupid) and compares the checksum to (the checksum
    it would calculate based on) the data (actually on the tape) to check data
    integrity. If the CRC and data don't match, there's a problem. It's
    usually a dirty drive (clean it) or old tape (replace it). Check the
    properties of that tape in BE; if it's one of your oldest tapes, has had
    more data written to it than average (for your tapes), has a lot of soft
    errors or even a few hard errors, then retire that tape. Heck, retire it
    anyway; that tape's a lot cheaper than the data you're protecting. If you
    can get it to cleanly do a "copy" type fullsystem b/u, you might retire it
    as an archive, but I wouldn't bet my home or family on its integrity. A
    good tape rotation and drive cleaning strategy will usually prevent these
    problems, but old drives can cause you grief as they fail, no matter how
    much you clean them. I usually buy two identical drives at a time; that
    way, even if the drive fails, I can install the spare and restore from tapes
    that have hardware compression w/o fear.

    Andy

    "Dan Star" wrote in message
    news:3B151ACE.7FEAB9F0@engman-taylor.com...
    > Hi,
    >
    > Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571. The
    > daily backup failed last night and turns out there was a Cyclic
    > Redundancy Check data error in the log during the VERIFY. I found
    > TechNote ID: 192216 but it doesn't explain what the error means just
    > possible causes. I did a test restore of a sampling of files and the
    > restore went OKAY so I don't know if I can rely on the tape or not.
    > Could someone shed some light on this?
    >
    > Regards,
    > Dan




  3. Re: Meaning of Cyclic Redundancy Check Error?

    So the error I got could be for just one block of data then with the
    rest being fine? I am thinking if I had a serious problem that this
    error would be listed many times in the log; or does the verify stop at
    the first CRC error?

    Dan

    Andy wrote:
    >
    > A CRC is a checksum calculated from the contents of the data for which it
    > verifies integrity. BE does a read on the tape after b/u (unless you turn
    > this off...would be very stupid) and compares the checksum to (the checksum
    > it would calculate based on) the data (actually on the tape) to check data
    > integrity. If the CRC and data don't match, there's a problem. It's
    > usually a dirty drive (clean it) or old tape (replace it). Check the
    > properties of that tape in BE; if it's one of your oldest tapes, has had
    > more data written to it than average (for your tapes), has a lot of soft
    > errors or even a few hard errors, then retire that tape. Heck, retire it
    > anyway; that tape's a lot cheaper than the data you're protecting. If you
    > can get it to cleanly do a "copy" type fullsystem b/u, you might retire it
    > as an archive, but I wouldn't bet my home or family on its integrity. A
    > good tape rotation and drive cleaning strategy will usually prevent these
    > problems, but old drives can cause you grief as they fail, no matter how
    > much you clean them. I usually buy two identical drives at a time; that
    > way, even if the drive fails, I can install the spare and restore from tapes
    > that have hardware compression w/o fear.
    >
    > Andy
    >
    > "Dan Star" wrote in message
    > news:3B151ACE.7FEAB9F0@engman-taylor.com...
    > > Hi,
    > >
    > > Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571. The
    > > daily backup failed last night and turns out there was a Cyclic
    > > Redundancy Check data error in the log during the VERIFY. I found
    > > TechNote ID: 192216 but it doesn't explain what the error means just
    > > possible causes. I did a test restore of a sampling of files and the
    > > restore went OKAY so I don't know if I can rely on the tape or not.
    > > Could someone shed some light on this?
    > >
    > > Regards,
    > > Dan


  4. Re: Meaning of Cyclic Redundancy Check Error?

    Your system log will also show that the tape device has a bad block (maybe
    says if there's more...don't know, never had it). What's the prob. w/
    running the backup job again?

    "Dan Star" wrote in message
    news:3B1532E2.A3422420@engman-taylor.com...
    > So the error I got could be for just one block of data then with the
    > rest being fine? I am thinking if I had a serious problem that this
    > error would be listed many times in the log; or does the verify stop at
    > the first CRC error?
    >
    > Dan
    >
    > Andy wrote:
    > >
    > > A CRC is a checksum calculated from the contents of the data for which

    it
    > > verifies integrity. BE does a read on the tape after b/u (unless you

    turn
    > > this off...would be very stupid) and compares the checksum to (the

    checksum
    > > it would calculate based on) the data (actually on the tape) to check

    data
    > > integrity. If the CRC and data don't match, there's a problem. It's
    > > usually a dirty drive (clean it) or old tape (replace it). Check the
    > > properties of that tape in BE; if it's one of your oldest tapes, has had
    > > more data written to it than average (for your tapes), has a lot of soft
    > > errors or even a few hard errors, then retire that tape. Heck, retire

    it
    > > anyway; that tape's a lot cheaper than the data you're protecting. If

    you
    > > can get it to cleanly do a "copy" type fullsystem b/u, you might retire

    it
    > > as an archive, but I wouldn't bet my home or family on its integrity. A
    > > good tape rotation and drive cleaning strategy will usually prevent

    these
    > > problems, but old drives can cause you grief as they fail, no matter how
    > > much you clean them. I usually buy two identical drives at a time; that
    > > way, even if the drive fails, I can install the spare and restore from

    tapes
    > > that have hardware compression w/o fear.
    > >
    > > Andy
    > >
    > > "Dan Star" wrote in message
    > > news:3B151ACE.7FEAB9F0@engman-taylor.com...
    > > > Hi,
    > > >
    > > > Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571. The
    > > > daily backup failed last night and turns out there was a Cyclic
    > > > Redundancy Check data error in the log during the VERIFY. I found
    > > > TechNote ID: 192216 but it doesn't explain what the error means just
    > > > possible causes. I did a test restore of a sampling of files and the
    > > > restore went OKAY so I don't know if I can rely on the tape or not.
    > > > Could someone shed some light on this?
    > > >
    > > > Regards,
    > > > Dan




  5. Re: Meaning of Cyclic Redundancy Check Error?

    Nothing, just trying to get a better understanding of the situation.

    Andy wrote:
    >
    > Your system log will also show that the tape device has a bad block (maybe
    > says if there's more...don't know, never had it). What's the prob. w/
    > running the backup job again?
    >
    > "Dan Star" wrote in message
    > news:3B1532E2.A3422420@engman-taylor.com...
    > > So the error I got could be for just one block of data then with the
    > > rest being fine? I am thinking if I had a serious problem that this
    > > error would be listed many times in the log; or does the verify stop at
    > > the first CRC error?
    > >
    > > Dan
    > >
    > > Andy wrote:
    > > >
    > > > A CRC is a checksum calculated from the contents of the data for which

    > it
    > > > verifies integrity. BE does a read on the tape after b/u (unless you

    > turn
    > > > this off...would be very stupid) and compares the checksum to (the

    > checksum
    > > > it would calculate based on) the data (actually on the tape) to check

    > data
    > > > integrity. If the CRC and data don't match, there's a problem. It's
    > > > usually a dirty drive (clean it) or old tape (replace it). Check the
    > > > properties of that tape in BE; if it's one of your oldest tapes, has had
    > > > more data written to it than average (for your tapes), has a lot of soft
    > > > errors or even a few hard errors, then retire that tape. Heck, retire

    > it
    > > > anyway; that tape's a lot cheaper than the data you're protecting. If

    > you
    > > > can get it to cleanly do a "copy" type fullsystem b/u, you might retire

    > it
    > > > as an archive, but I wouldn't bet my home or family on its integrity. A
    > > > good tape rotation and drive cleaning strategy will usually prevent

    > these
    > > > problems, but old drives can cause you grief as they fail, no matter how
    > > > much you clean them. I usually buy two identical drives at a time; that
    > > > way, even if the drive fails, I can install the spare and restore from

    > tapes
    > > > that have hardware compression w/o fear.
    > > >
    > > > Andy
    > > >
    > > > "Dan Star" wrote in message
    > > > news:3B151ACE.7FEAB9F0@engman-taylor.com...
    > > > > Hi,
    > > > >
    > > > > Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571. The
    > > > > daily backup failed last night and turns out there was a Cyclic
    > > > > Redundancy Check data error in the log during the VERIFY. I found
    > > > > TechNote ID: 192216 but it doesn't explain what the error means just
    > > > > possible causes. I did a test restore of a sampling of files and the
    > > > > restore went OKAY so I don't know if I can rely on the tape or not.
    > > > > Could someone shed some light on this?
    > > > >
    > > > > Regards,
    > > > > Dan


  6. Re: Meaning of Cyclic Redundancy Check Error?

    I hear ya. Very frustrating to "solve" a problem w/o first figuring it
    out...just makes you feel a little more unprepared...ya know?

    "Dan Star" wrote in message
    news:3B1562B8.182AD801@engman-taylor.com...
    > Nothing, just trying to get a better understanding of the situation.
    >
    > Andy wrote:
    > >
    > > Your system log will also show that the tape device has a bad block

    (maybe
    > > says if there's more...don't know, never had it). What's the prob. w/
    > > running the backup job again?
    > >
    > > "Dan Star" wrote in message
    > > news:3B1532E2.A3422420@engman-taylor.com...
    > > > So the error I got could be for just one block of data then with the
    > > > rest being fine? I am thinking if I had a serious problem that this
    > > > error would be listed many times in the log; or does the verify stop

    at
    > > > the first CRC error?
    > > >
    > > > Dan
    > > >
    > > > Andy wrote:
    > > > >
    > > > > A CRC is a checksum calculated from the contents of the data for

    which
    > > it
    > > > > verifies integrity. BE does a read on the tape after b/u (unless

    you
    > > turn
    > > > > this off...would be very stupid) and compares the checksum to (the

    > > checksum
    > > > > it would calculate based on) the data (actually on the tape) to

    check
    > > data
    > > > > integrity. If the CRC and data don't match, there's a problem.

    It's
    > > > > usually a dirty drive (clean it) or old tape (replace it). Check

    the
    > > > > properties of that tape in BE; if it's one of your oldest tapes, has

    had
    > > > > more data written to it than average (for your tapes), has a lot of

    soft
    > > > > errors or even a few hard errors, then retire that tape. Heck,

    retire
    > > it
    > > > > anyway; that tape's a lot cheaper than the data you're protecting.

    If
    > > you
    > > > > can get it to cleanly do a "copy" type fullsystem b/u, you might

    retire
    > > it
    > > > > as an archive, but I wouldn't bet my home or family on its

    integrity. A
    > > > > good tape rotation and drive cleaning strategy will usually prevent

    > > these
    > > > > problems, but old drives can cause you grief as they fail, no matter

    how
    > > > > much you clean them. I usually buy two identical drives at a time;

    that
    > > > > way, even if the drive fails, I can install the spare and restore

    from
    > > tapes
    > > > > that have hardware compression w/o fear.
    > > > >
    > > > > Andy
    > > > >
    > > > > "Dan Star" wrote in message
    > > > > news:3B151ACE.7FEAB9F0@engman-taylor.com...
    > > > > > Hi,
    > > > > >
    > > > > > Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571.

    The
    > > > > > daily backup failed last night and turns out there was a Cyclic
    > > > > > Redundancy Check data error in the log during the VERIFY. I found
    > > > > > TechNote ID: 192216 but it doesn't explain what the error means

    just
    > > > > > possible causes. I did a test restore of a sampling of files and

    the
    > > > > > restore went OKAY so I don't know if I can rely on the tape or

    not.
    > > > > > Could someone shed some light on this?
    > > > > >
    > > > > > Regards,
    > > > > > Dan




  7. Re: Meaning of Cyclic Redundancy Check Error?

    this error occurs when the tape needs to be rewinded constantly to read the
    information in other words the tape is trying to copy faster then the
    information is being sent.
    "Dan Star" wrote in message
    news:3B151ACE.7FEAB9F0@engman-taylor.com...
    > Hi,
    >
    > Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571. The
    > daily backup failed last night and turns out there was a Cyclic
    > Redundancy Check data error in the log during the VERIFY. I found
    > TechNote ID: 192216 but it doesn't explain what the error means just
    > possible causes. I did a test restore of a sampling of files and the
    > restore went OKAY so I don't know if I can rely on the tape or not.
    > Could someone shed some light on this?
    >
    > Regards,
    > Dan




  8. Re: Meaning of Cyclic Redundancy Check Error?

    No it doesn't

    It means that when the drive computes the CRC value to "verify" the write, that
    the value computed is different than the value read from the tape.

    See http://seer.support.veritas.com/docs/192216.htm for Veritas solutions to
    this error.

    "." wrote:

    > this error occurs when the tape needs to be rewinded constantly to read the
    > information in other words the tape is trying to copy faster then the
    > information is being sent.
    > "Dan Star" wrote in message
    > news:3B151ACE.7FEAB9F0@engman-taylor.com...
    > > Hi,
    > >
    > > Running WinNT Server 4 SP6a with BEx Server Edition v8.5 R3571. The
    > > daily backup failed last night and turns out there was a Cyclic
    > > Redundancy Check data error in the log during the VERIFY. I found
    > > TechNote ID: 192216 but it doesn't explain what the error means just
    > > possible causes. I did a test restore of a sampling of files and the
    > > restore went OKAY so I don't know if I can rely on the tape or not.
    > > Could someone shed some light on this?
    > >
    > > Regards,
    > > Dan



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