mount issue with virtual tapes

[dkastens]

Hi,
I defined a dd6400 vtl with lto8 drives and tapes. The backup works, but I see, that during a backup the tape seems to be mounted and dismounted for every single file. After a while, the "query volume" command shows, that the tape has been mountet more than 3000 times!!! The actlog is full of messages:

03.04.24 09:52:45	ANR0511I Session 12942 opened output volume A00000L8. (SESSION: 12942)
03.04.24 09:52:45	ANR0514I Session 12942 closed volume A00000L8. (SESSION: 12942)
03.04.24 09:52:45	ANR0511I Session 12942 opened output volume A00000L8. (SESSION: 12942)
03.04.24 09:52:46	ANR0514I Session 12942 closed volume A00000L8. (SESSION: 12942)
03.04.24 09:52:46	ANR0511I Session 12942 opened output volume A00000L8. (SESSION: 12942)
03.04.24 09:52:46	ANR0514I Session 12942 closed volume A00000L8. (SESSION: 12942)

Do you have any idea what could be wrong or is this a normal behaviour of virtual tapes (what I doubt)?

Regards,
Dirk

 

[moon-buddy]

Haven't configured a Data Domain VTL for a while. Have you looked at the TSM server device settings for the Tape pool: "q devclass <tape_pool_name> f=d"? Look at "Mount wait" and "mount retention" parameters.

What are the value set? Try increasing this.

Mine is set for 60 for mount wait and 3 for mount retention. Time is in minutes.

 

[EricvanLoon]

Open/close messages are not the same as mount (ANR8337I) and dismount (ANR8468I) messages.

 

[dkastens]

Default values are 60 minutes for both attributes. But I also think, that they have nothing to do with the open/close messages.

 

[dkastens]

I just started a new test. I backed up about 20.000 files with a total size of 2,3 GB. After the backup, the vtl tape shows "Number of Times Mounted: 521". Then I searched the activity log for messages A0511I (Session 11959 opened output volume A00000L8) and A0514I (Session 11959 closed volume A00000L8). Both appear exactly 521 times in the log.
The open/close messages also appear for real lto volumes, but not so many. Maybe this is normal behavior.

 

[LED888]

03.04.24 09:52:45	ANR0511I Session 12942 opened output volume A00000L8. (SESSION: 12942)
03.04.24 09:52:45	ANR0514I Session 12942 closed volume A00000L8. (SESSION: 12942)

... Maybe this is normal behavior.

No.
From the snippet of the actlog that was provided, there is no time gap between messages.
The tape is dismounted as soon as the tape is mounted. This is not normal for a VTL or a physical tape library.

If it was during a restore, will see a lot of tapes being mounted and dismounted but there will be time between the mount and dismount.

For backup, would not expect to see a lot of tapes being mounted and dismounted.
Unless we have collocation by filespace, if this was the case.
Will notice that a lot of scratch tapes are being used up.

There is some thing going on.
With the actlog flooded with ANR0511I and ANR0514I, I would start looking at the actlog when the backup start and completed. If we know the name of the node that perform the backup.
In the actlog, do a search on the node name and note the session and process number.
Check to see if there are any errors at the beginning and end of the backup.

Not sure what os is hosting the TSM Server.
If its AIX, confirm that all the tape drives are in an available state.
If its it a define state, may need to run cfgmgr to get the tape back into an available state.


Good Luck,
Sias

 

[dkastens]

Hi Sias,
thanks for your reply. The TSM server is running RedHat EL 8.7.
The vtl volume is not mounted and dismounted, but it is opened and closed hundreds of times. The complete actlog looks like this:

04/05/24 12:28:46 ANR8337I LTO volume A00000L8 mounted in drive DD6400_D01
(/dev/tape/by-name/dd6400_d01). (SESSION: 11947)
04/05/24 12:28:46 ANR1340I Scratch volume A00000L8 is now defined in
storage pool VTLPOOL. (SESSION: 11947)
04/05/24 12:28:46 ANR0511I Session 11947 opened output volume A00000L8.
(SESSION: 11947)
04/05/24 12:28:54 ANR0514I Session 11947 closed volume A00000L8. (SESSION:
11947)
04/05/24 12:29:05 ANR8329I LTO volume A00000L8 is mounted R/W in drive
DD6400_D01 (/dev/tape/by-name/dd6400_d01), status: IDLE.
(SESSION: 11602)
04/05/24 12:30:09 ANR0511I Session 11959 opened output volume A00000L8.
(SESSION: 11959)
04/05/24 12:30:15 ANR0514I Session 11959 closed volume A00000L8. (SESSION:
11959)
...
04/05/24 12:53:15 ANR8330I LTO volume A00000L8 is mounted R/W in drive
DD6400_D01 (/dev/tape/by-name/dd6400_d01), status: IN
USE.
04/05/24 12:53:17 ANR0514I Session 11959 closed volume A00000L8. (SESSION:
11959)
04/05/24 12:58:17 ANR8325I Dismounting volume A00000L8 - 5 minute mount
retention expired.
04/05/24 12:58:17 ANR8336I Verifying label of LTO volume A00000L8 in drive
DD6400_D01 (/dev/tape/by-name/dd6400_d01). (SESSION:
11947)
04/05/24 12:58:17 ANR8468I LTO volume A00000L8 dismounted from drive
DD6400_D01 (/dev/tape/by-name/dd6400_d01) in library
DD6400. (SESSION: 11947)
This all looks normal to me, except for the open/closed messages. I wonder if there is an option or parameter in TSM to control this behaviour. Or maybe it's the VTL configuration.

 

[dkastens]

I found the solution here on the IBM support pages.
After setting the option KEEPMP=yes for the client, the open/close messages disappeared. The problem was, that the directories are stored via DIRMC on another diskpool. Every time the client backed up a directory, the session closed the tape volume before and reopened it afterwards. I started a new backup, and there was only one mount of the tape with opening the volume at the beginning, and one closing of the volume and dismounting the tape at the end of the session.

 

[LED888]

The tape is dismounted as soon as the tape is mounted.

Opps...my bad.
Sorry, I meant to say "The tape is close as soon as the tape is open."

Glad to hear that you found setting the KEEPMP=Yes resolve the issue.

Good Luck,
Sias