Drive Selection

[technimdaxviii]

How does netbakup select the driver to use? We have 2 drivers for StorageTek SL150. But log show only one driver was used for different backups.

[Nicolai]

 There a couple of things to check:

For the storage unit, what is the value of "number of drives" set to ? (2 should be the value)

For the storage unit, what is the "max concurrent write drives" drives set to ? (2 shoud be the value).

[Mike_Gavrilov]

If we're talking about your case when check Nikolai's recommendations first. 

If you just want to know how it works. Under the hood NetBackup has group of daemons (nbrb, mds, da, nbemm) sometimes called IRM (Intelligent Resource Manager). They monitor drives' state and select which drive should used for a job.

[Marianne · Accepted solution]

If configuration is correct and both drives are UP, NBU will automatically load balance the available tape drives.

Please show us config and drive status:

/usr/openv/netbackup/bin/admincmd/bpstulist -U

/usr/openv/volmgr/bin/tpconfig -l

/usr/openv/volmgr/bin/vmoprcmd -d

[Genericus]

It has been my experience that the basic statement Marianne made - "If configuration is correct and both drives are UP, NBU will automatically load balance the available tape drives" is MOSTLY true (especially if storage unit is set to round robin)

NetBackup should take a bunch of other things into account -

are the drives shared? NetBackup will give priority to media server already allocated to minimize unload and loading

are multiple pools used? NetBackup will give priority to writing to pool already loaded.

With all other things equal - if you stop everything then start clean, it should load the drives alphabetically in order and round robin them - which when planning, means you can balance things like HBA and NIC using the drive naming...

[technimdaxviii]

Hi Marianne,

Thank you for the response. It show the drive was down. After bringing it up, both drives are now used.

Regards,
J

root@hq-vnb:~# /usr/openv/volmgr/bin/tpconfig -l
Device Robot Drive       Robot                    Drive                 Device         Second
Type     Num Index  Type DrNum Status  Comment    Name                  Path           Device Path
robot      0    -    TLD    -       -  -          -                     /dev/sg/c0tw500104f000d23aa7l1
  drive    -    0 hcart3    1    DOWN  -          HP.ULTRIUM6-SCSI.000  /dev/rmt/0cbn  drive    -    1 hcart3    2      UP  -          HP.ULTRIUM6-SCSI.001  /dev/rmt/1cbn
root@hq-vnb:~#
root@hq-vnb:~# 
root@hq-vnb:~# /usr/openv/volmgr/bin/vmoprcmd -d

                                PENDING REQUESTS

                                     <NONE>

                                  DRIVE STATUS

Drv Type   Control  User      Label  RecMID  ExtMID  Ready   Wr.Enbl.  ReqId
  0 hcart3 DOWN-TLD             -                     No       -         0  
  1 hcart3   TLD                -                     No       -         0 

                             ADDITIONAL DRIVE STATUS

Drv DriveName            Shared    Assigned        Comment                   
  0 HP.ULTRIUM6-SCSI.000  Yes      -                                         
  1 HP.ULTRIUM6-SCSI.001  Yes      -  

root@hq-vnb:~# tpconfig -l
Device Robot Drive       Robot                    Drive                 Device         Second
Type     Num Index  Type DrNum Status  Comment    Name                  Path           Device Path
robot      0    -    TLD    -       -  -          -                     /dev/sg/c0tw500104f000d23aa7l1
  drive    -    0 hcart3    1      UP  -          HP.ULTRIUM6-SCSI.000  /dev/rmt/0cbn  drive    -    1 hcart3    2      UP  -          HP.ULTRIUM6-SCSI.001  /dev/rmt/1cbn
root@hq-vnb:~# vmoprcmd -d

                                PENDING REQUESTS

                                     <NONE>

                                  DRIVE STATUS

Drv Type   Control  User      Label  RecMID  ExtMID  Ready   Wr.Enbl.  ReqId
  0 hcart3   TLD                -                     No       -         0    1 hcart3   TLD                -                     No       -         0  

                             ADDITIONAL DRIVE STATUS

Drv DriveName            Shared    Assigned        Comment                   
  0 HP.ULTRIUM6-SCSI.000  Yes      -                                         
  1 HP.ULTRIUM6-SCSI.001  Yes      -