Forum Discussion

Enoc's avatar
Enoc
Level 2
11 years ago
Solved

How to check no. of times tape has been full.

Hi All,

we are using Symentec Netbackup 7.0.1 with LTO4 & LTO5 Tapes, our master server runs on HP_UX OS, I want to know that is there any way to know that how many times tape has been full from start of time of a specific tape, as i want to change the Tapes before its end of life cycle to avoid any disaster. 

For.e.g :- i want to know the no. of times Tape01 has been full from its 1st use.

Thanks in Advance.

 

 

7.1.x and Earlier
Backup and Recovery
HP-UX
Managing Backup Devices
NetBackup
  • sdo's avatar
    sdo
    11 years ago
    My understanding was that most tape vendors warrant media for about 200 full writes, which is almost the same as saying 200 mounts - you'll see why below... ...and I need to re-iterate that Martin's post re shoe-shine wear and tear is very important. Afaik - LTO media are track based, and that they wind/write/read backwards and forwards, so to actually fill an LTO media involves several complete winds forward and backwards - I believe the number of tracks changes/changed across different generations of the LTO family - so for example to fill an LTO media with 8 tracks, involves 8 traversals of the entire length of the media - forward/back/forward/back...etc. What this means is that for an 8 track LTO media, then the media has been fully wound over once by the time it contains 1/8 of its capacity. So, for an 8 track media, that has a life span of 200 mounts, then it could well have been fully wound 1600 times! Hence what appears to be a low mount count life span of 200 mounts. And remember each time a media is re-mounted, for append, or restore, then this involves more winding along the length of the media. So it is easily possible to exceed 2000 full winds. Martin's point is critical. If your infrastructure is unable to meet minimum streaming speeds, then your media will wear out very quickly. Final point. Not all LTO drives are the same. Some have speed stepping at different levels to each other. E.g. vendor A tape drive might speed step at 40, 60, 80, 120 MB/s - whereas vendor B drive might have only one minimum speed step of 80MB/s.
  • mph999's avatar
    mph999
    11 years ago

    Nope, doesn't work like that unfortunately.

    The mount count has little or no reflection on media condition.

    The media count is nowhere near close to the total number of passes, as for example LTO5, the tape may mount once and be written till it is full.  The tape would have made 80 end-to-end passes to do this, LTO4 would have been 56.

    One interesting thing that was seen with Storsentry, is that analysis of the results from all UK companies using it at the time, was that out of the all the media that the companies would normally have replaced due to no uses /age etc ... it was found that in fact only about 4% was actually defective - which again is more evidence that no. mounts etc .. is in no way any use to determine media condition.

     

     

  • Mark_Solutions's avatar
    Mark_Solutions
    11 years ago

    There is nothing in NetBackup that will do this for you but it may be that your tape library already has this information available.

    Quatum libraries store some data and if you have the advanced reporting option / license then what you are looking for may be available to you via the reports section of the tape library interface

    Hope this helps

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  • RiaanBadenhorst's avatar
    RiaanBadenhorst
    Level 6
    11 years ago

    NetBackup tracks the mounts, and if its full. I don't see anyway to show what you're asking for unless you've been tracking the instance when the tape got full yourself. The mounts are relevant, I don't think the percentage used makes much of a difference.
     

  • Enoc's avatar
    Enoc
    Level 2
    11 years ago

    I can track all mount points but doesn't stats no. of time tape is full as backup size is not specific,we use scratchpool so we don't track full Tape & resue since software does it.

  • mph999's avatar
    mph999
    Level 6
    11 years ago

    What you need is a product called StorSentry.

    ftp://ftp.software.ibm.com/storage/proven/hi-stor-te.pdf

    I'm not sure who markets this at the moment, but it was originally written by a company called Hi-Stor and monitors the conditions of the tapes and drives at a low level, being able to predict tape failure.  I've used it, and seen it used in other companies and it works very very well.

    I did an investigation into tape condition, with the help of Imation.  According to the 'tape expert' I was speaking to, the number of mounts is irrelevant, tape life is more to do with haow the tapes are handled, stored, condition of the drives and most importantly if they are run above their streaming speed.

    A tape that is 'shoe-shined' can show signs of increased wear within a few uses, hence the reason the number of mounts is not generally useful.

    Editted to add ...

    If the tape is always run in perfect condtions, always above min streaming speed , then yes, no of mounts would then be more useful.  In reality this rarely happens.

  • Enoc's avatar
    Enoc
    Level 2
    11 years ago

    My Client want to replace media as per usage, they want to replace after certain no. of Time specific Tape is used fully, the Product you mention may be helpfull in different companies but my company wants the no. of times media is fully used.

  • sdo's avatar
    sdo
    Moderator
    11 years ago
    My understanding was that most tape vendors warrant media for about 200 full writes, which is almost the same as saying 200 mounts - you'll see why below... ...and I need to re-iterate that Martin's post re shoe-shine wear and tear is very important. Afaik - LTO media are track based, and that they wind/write/read backwards and forwards, so to actually fill an LTO media involves several complete winds forward and backwards - I believe the number of tracks changes/changed across different generations of the LTO family - so for example to fill an LTO media with 8 tracks, involves 8 traversals of the entire length of the media - forward/back/forward/back...etc. What this means is that for an 8 track LTO media, then the media has been fully wound over once by the time it contains 1/8 of its capacity. So, for an 8 track media, that has a life span of 200 mounts, then it could well have been fully wound 1600 times! Hence what appears to be a low mount count life span of 200 mounts. And remember each time a media is re-mounted, for append, or restore, then this involves more winding along the length of the media. So it is easily possible to exceed 2000 full winds. Martin's point is critical. If your infrastructure is unable to meet minimum streaming speeds, then your media will wear out very quickly. Final point. Not all LTO drives are the same. Some have speed stepping at different levels to each other. E.g. vendor A tape drive might speed step at 40, 60, 80, 120 MB/s - whereas vendor B drive might have only one minimum speed step of 80MB/s.
  • sdo's avatar
    sdo
    Moderator
    11 years ago
    What this means to me is that I am able to base my media usage on the NetBackup mount count because of the track based nature of LTO media. I mean that because the media are track based, then the mount count is quite close to the wind/pass/write/read count - and so, if a vendor warrants media for 200 uses, then a mount count of 200 is the time at which media should be changed.
  • Enoc's avatar
    Enoc
    Level 2
    11 years ago

    Mount Point can't be count has full usage as in my case it takes min 40 Counts to make media Full, Tapes have already reached more then 1000 mount points but till now i have not faced any issue with Tape.

  • mph999's avatar
    mph999
    Level 6
    11 years ago

    Nope, doesn't work like that unfortunately.

    The mount count has little or no reflection on media condition.

    The media count is nowhere near close to the total number of passes, as for example LTO5, the tape may mount once and be written till it is full.  The tape would have made 80 end-to-end passes to do this, LTO4 would have been 56.

    One interesting thing that was seen with Storsentry, is that analysis of the results from all UK companies using it at the time, was that out of the all the media that the companies would normally have replaced due to no uses /age etc ... it was found that in fact only about 4% was actually defective - which again is more evidence that no. mounts etc .. is in no way any use to determine media condition.

     

     

  • Mark_Solutions's avatar
    Mark_Solutions
    Level 6
    11 years ago

    There is nothing in NetBackup that will do this for you but it may be that your tape library already has this information available.

    Quatum libraries store some data and if you have the advanced reporting option / license then what you are looking for may be available to you via the reports section of the tape library interface

    Hope this helps