Forum Discussion

Meg_G's avatar
Meg_G
Level 4
14 years ago

Media Error Threshold

I'm new to NBU...going live next week.  I am wondering what counts as a "media" error.  I'm currently a Backup Exec user, and see some tapes with soft read and soft write errors on them.  Only time I have ever seen a "hard" error is when a drive has failed.  Soft errors are generally always under 10, depends how old the tape is.  It is LTO 2 tape, in an HP MSL4048 robot (4 drives).

Question is, will these soft errors count towards the media errors?  I'm concerend about the default setting of 2 for the media error threshold, but don't want to set it higher if I don't need to.

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  • Andy_Welburn's avatar
    Andy_Welburn
    14 years ago

    the default time window of 12 hours for tapes to be frozen or drives to be downed - are you expecting to exceed this?

    If you constantly do get frozen media/downed tapes then I would seriously suspect the resources (tape/drive).

    Unfortunately can't comment on what counts as a soft error in BE - but if it constitutes a read or write error then I would imagine that it will count towards the threshold - but again, only within that time window.

    ***EDIT***
    I'm presuming you've already referenced the following:

    DOCUMENTATION: How Veritas NetBackup determines if a tape should be frozen or the status of a tape drive should be changed to down, and how to change this behavior
    http://www.symantec.com/business/support/index?page=content&id=TECH66391

    This T/N references the NB6.0 Media Manager Guide which provides a list of tape alert codes & what the default actions for these are (e.g. freeze media, down drive etc) which may also assist:

    http://www.symantec.com/business/support/index?page=content&id=TECH43934

  • Andy_Welburn's avatar
    Andy_Welburn
    Level 6
    14 years ago

    the default time window of 12 hours for tapes to be frozen or drives to be downed - are you expecting to exceed this?

    If you constantly do get frozen media/downed tapes then I would seriously suspect the resources (tape/drive).

    Unfortunately can't comment on what counts as a soft error in BE - but if it constitutes a read or write error then I would imagine that it will count towards the threshold - but again, only within that time window.

    ***EDIT***
    I'm presuming you've already referenced the following:

    DOCUMENTATION: How Veritas NetBackup determines if a tape should be frozen or the status of a tape drive should be changed to down, and how to change this behavior
    http://www.symantec.com/business/support/index?page=content&id=TECH66391

    This T/N references the NB6.0 Media Manager Guide which provides a list of tape alert codes & what the default actions for these are (e.g. freeze media, down drive etc) which may also assist:

    http://www.symantec.com/business/support/index?page=content&id=TECH43934

  • Kiran_Bandi's avatar
    Kiran_Bandi
    Level 6
    14 years ago

    Read and write errors on the media counts. NetBackup will freeze a media if it encounters media errors more than the value specified under Media_Error_Threshold within the time window specified. Default values: 2 errors within 12 hours. I feel no need to increase the value, but if you want you can.

    Regards.

  • Meg_G's avatar
    Meg_G
    Level 4
    14 years ago

    Ah, thanks Andy.  I didn't realize there there two separate thresholds for media and drive errors.  Either way, sounds like this will be a trial and error process!  I don't expect to run into a problem, but who knows.

     

    Perhaps someone else has some comments regarding the Backup Exec soft errors....I'll wait and if not mark your post as a solution, Andy.

  • Andy_Welburn's avatar
    Andy_Welburn
    Level 6
    14 years ago

    Have been running the default thresholds since inception of 4.5 here (presuming the thresholds were around then!) & the only time that we've had errors reported have been when there were issues - flaky drives, old media, write-protected media etc. Never found excessive 'bogus' issues, so you should be ok.