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bc1410's avatar
bc1410
Level 6
4 months ago

netbackup media tape duplication / concern

Hello

 

My question is regarding "preserve multiplexing" in duplicating backup images on media tapes in NetBackup from LTO7's to LTO8 via the netbackup admin console.

Our layout is this.  Netbackup 10.5.0.1 RHEL8 environment running on a single server that serves as both master/media.  This netbackup environment has been around for sometime - another words it has been upgraded from the early days of NBU 7* to the current version its on now with multiple hardware refreshes and OS refreshes.

Our storage units are the following

We have two Overland  LTO7 libraries and we also no have 2 overland LTO8 libraries.

The storage units from the admin console look like this - 

the name ending in tld-0 and tld-1 are the LTO7 tape libraries and the tld-2 and tld-3 are the LTO8 libraries.

We are wanting to duplicate our LTO7 archive tapes and/or tapes that have an INFINTY expired date to the new LTO8 tapes.

A little history behind this on our project we had a previous co-worker years ago that duplicated our LTO5s to the current LTO7s and I was able to find some of his notes and on the admin console CATALOG section where you can perform the "duplicate" option he had also stated to check the box on the gui to PRESERVE MULTIPLEXING.    So basically this is were my question has come about as I ran a quick test to perform a duplication of some images on a LTO7 tape to duplicate them to a LTO8 tape.  But my duplication job failed right away with a status 154 ((154) storage unit characteristics mismatched to request )  

detailed status of the job showed this - 

Aug 22, 2025, 3:52:27 PM - begin Duplicate

Aug 22, 2025, 3:52:28 PM - Error nbjm (pid=5536)  NetBackup status: 154, EMM status: Storage unit is not compatible

Aug 22, 2025, 3:52:28 PM - Error nbjm (pid=5536)  NetBackup status: 154, EMM status: Storage unit is not compatible

Aug 22, 2025, 3:52:28 PM - Error nbjm (pid=5536)  NetBackup status: 154, EMM status: Storage unit is not compatible

Aug 22, 2025, 3:52:28 PM - Error nbjm (pid=5536)  NetBackup status: 154, EMM status: Storage unit is not compatible

Aug 22, 2025, 3:52:28 PM - end Duplicate; elapsed time 0:00:01

Aug 22, 2025, 3:52:28 PM - requesting resource  kbs-pgrid-1-hcart-robot-tld-2

Aug 22, 2025, 3:52:28 PM - requesting resource  0832L7

Aug 22, 2025, 3:52:28 PM - reserving resource 0832L7

Aug 22, 2025, 3:52:28 PM - Error nbjm (pid=5531) NetBackup status: 154, EMM status: Storage unit is not compatible

Aug 22, 2025, 3:52:28 PM - Error nbjm (pid=5531) NetBackup status: 154, EMM status: Storage unit is not compatible

Aug 22, 2025, 3:52:28 PM - Error nbjm (pid=5531) NetBackup status: 154, EMM status: Storage unit is not compatible

Aug 22, 2025, 3:52:28 PM - Error nbjm (pid=5531) NetBackup status: 154, EMM status: Storage unit is not compatible

storage unit characteristics mismatched to request  (154)

So as you can see in SNIP above the storage units all have multiplexing set to 1 which I believe means its not active on the storage units/libraries.  But just about all the policies have the multiplexing enable except I believe the MSSQL policies.   

I myself do not recall changing the multiplex option on the storage units.  When I recently added the Overland LTO8 libraries I just made them the same setting as what was in place for the LTO7 libraries.  

I was able to get my test duplication job to run but I had to change the multiplexing from 1 to 32 on the LTO8 library (destination library for duplication).  

Am i correct in that I need to have multiplexing enabled on the libraries for the destination library in order to preserve multiplexing.  In GENERAL If the policies have multiplexing set should the drives as well have it set to something other then 1?

I can see in the admin console under MEDIA STATUS that a lot of the old LTO7 tapes that were probably from the previous duplication task done by the former co-workers has a MEDIA status =  Active multiplexed or some have FULL Multiplexed.

Then I see some of the newer LTO7 series of tapes have MEDIA STATUS = FULL

So should the storage UNITS have MULTIPLEX enabled (something other then 1) if the POLICIES have multiplex set to something other then 1.  ?  Any advice or suggestions would be appreciated.

Im thinking we need to have the Storage units set to multiplexing permanently (something other then 1) not just for the duplication task but for normal backups but honestly Im not sure.

 

Thanks

BC

3 Replies

  • quebek's avatar
    quebek
    Moderator
    4 months ago

    Hello,

    Are you duplicating whole tapes or just selected backup images? If whole tapes than preserving MPX make sense - but the restore will be not the fastest, you are aware of this right? If selected images I would unchecked the preserve MPX button (well I am recalling things from my memory as  I did not deal with tapes for more than 5+ years now).

    https://www.veritas.com/support/en_US/article.100017626

    If you have to preserve MPX then create yet another STU on the LTO8 robot and set its MPX to match the source STU, then use this STU in duplication job - if you are afraid to do it on existing one STU.

    • bc1410's avatar
      bc1410
      Level 6
      4 months ago

      hi quebek​   Thank you very much for your reply.

      Yes we are planning on trying to duplicate all of our LTO7 tapes to LTO8's but for only one of the policy's / volume pool - our Archive policy/pool.   Using the Admin Console interface going under the Catalog section and then changing the Action to Duplicate.  Then we will search by Policy name and utilize the Date / time Range.  Then select the search Results catalog images and right click and select duplicate.  So I guess in a sense its duplicating the entire tape.    We will make the duplicate image on the LTO8 the primary and then after a successful duplication we will expire the LTO7 images to bring those tapes back to scratch.   Probably not neccessary but I know this is what the former Netbackup guy did when he duplicated the LTO5s to LTO7 years ago.

      Thanks for link I did stumble on that same link.  

      As I mentioned I tried to do a test to duplicate a few of the images that were from a Archival tape that had a media status of FULL Multiplex.  it failed right away with the status 154.  I mean Im guessing we should preserve the multiplex on tapes that have a media status of FULLY Multiplex - right?   Im not an advance Netbackup guy so not sure what effects of not preserving it.

      Some of the current LTO7 tapes have a media status of "Full Multiplex" so Im thinking we need to preserve this? right

      Bult like I mentioned previously also the current storage units (both LTO7 libraries and LTO8 libraries) all have multiplexing set to 1 which Im guessing that means its not enabled.  Im thinking at one point maybe the storage units like the LTO7 did have multiplex greater then 1.  I know you mentioned this "If you have to preserve MPX then create yet another STU on the LTO8 robot and set its MPX to match the source STU"   The source storage units are the LTO7 libraries and they are set to multiplexing = 1.  Do I just pick a number greater then 1 or what?  or I guess I need to look at the policies to see what it is set there.   

      As I mentioned Just about all the policies we have have multiplexing enabled (greater than 1) except for the MSSQL policies.  So I guess it doesn't matter if the policies have it enabled as it all depends if the storage units have it enabled - is this a correct assumption?  Im a little confused here on that.

       

      Thanks

      BC

      • quebek's avatar
        quebek
        Moderator
        4 months ago

        Hello,

        Well I think the target STU (Storage Unit) has to be configured as source in regards of MPX factor. That is why I proposed to create brand new STU on the SAME Tape Library and use it only for this duplication process. See the attached picture - its from newer release but same principle applies

        About duplication of whole tapes... I think this is only valid if you do select for THE TAPE in the duplication window. If I were you I wouldn't preserve MPX - as said earlier on this will speed up the duplication but for sure slow down the restores...