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Absent Member.. Gerasimov_Pavel Absent Member..
Absent Member..
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Drives allocation for specifications.

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Hello,

We have specification which need to start at the same time with the same drive pool (about 40 drives). Question is how we can configure this without busy drive  issue? Does HPDP have configuration like random select drive from allocated pool or  query for specification which starting in one time?

Best regards

Pavel

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Micro Focus Expert
Micro Focus Expert

Re: Drives allocation for specifications.

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The error message you get:

Cannot load exchanger medium (Target drive is busy.)"

is not related to drive but to the library robotics. DP is enough clever to not select drive one if already busy. You have an issue with the robotics control.

Have yo enabled lock on robotics ?

Probably you need also to change some robotics timeout to avoid it, but not having detailed info I cannot help. In any case it is correct to assign all 40 drive to the backup specification leaving to DP the chooice of which one to use. Dp will use the drive in the order you have selected in the backup specification. So if you have selected the entire library he will start from drive 1 to drive 40. If you want to change the allocation order select manually the drive in the order you like (i.e. start selecting from drive 40 backard). If you send the entire session log with the error may be we can help, otherwise run it in debug mode, open a support case and provide DP support the debug files.

Kind regards,

Dionisio

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5 Replies
Honored Contributor.. Marcos_A_DP Honored Contributor..
Honored Contributor..

Re: Drives allocation for specifications.

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Hello, you can select several drives for both backup jobs (not just only one) then assign all of the drives for that backup job the same media pool to use, this in both backup jobs. This assuming you have at least 2 drives or writers in your storage device.

At that point DP will automatically chose the available drive to start the backup operation.

Marcos A.
SW Support Technical Consultant
San Jose, Costa Rica
Hewlett Packard Enterprise
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Absent Member.. Gerasimov_Pavel Absent Member..
Absent Member..

Re: Drives allocation for specifications.

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Yes we  did the same, but in this case we face with next:

we have two policies which start together at the same time with the same drives configured on each. Then each specification choose first drive, then one of specification fails with critical message like this one:

"Cannot load exchanger medium (Target drive is busy.)"

or

"Cannot open exchanger control device (Mutex already locked.
System error: [122] The data area passed to a system call is too small.
)"

then specification tries to chose another drive, sometimes it successful somtimes session is aborted with the error:

"Aborting connection to BSM. Abort code -12."

Is it possible to start specifications at the same time without issues.

Best regards

Pavel

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Micro Focus Expert
Micro Focus Expert

Re: Drives allocation for specifications.

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Hello Pavel,

Let me try to comment on your posts.

"We have specification which need to start at the same time with the same drive pool (about 40 drives). "

Do you know how many drives each of the backup specification will use ?

Backup specification no. 1 - 5 drives or 10 drives or 20 drives ?
Backup specification no. 2 - 10 drives or 15 drives or 20 drives ?

I believe you have a tape library and it has 40 drives.

I dont see any reason why you need to define all 40 drives in 1 backup specification, more so if you expect these backup to run at the same time.

As an example :

If I have 4 backup specifications that need to run at the same time and I know they would use MIN 5 / MAX 10 drives, I would do :

Backup specification no. 1 - drive 1 to 10
Backup specification no. 2 - drive 11 to 20
Backup specification no. 3 - drive 21 to 30
Backup specification no. 4 - drive 31 to 40


"Question is how we can configure this without busy drive issue ?"

Do prevent busy drive issue, you have to avoid conflicts on the backups that are started/running on the same time. Key point is that during a DP backup (or restore), the drives should be dedicated to DP.

"Does HPDP have configuration like random select drive from allocated pool or query for specification which starting in one time?"

In your backup specification, you define concurrency and load balancing (min and max number of available devices), which will ensure that this backup will run at the time with enough drive that is free/idle/available.

If the drive you expect to be used is busy - used by other sessions, then you have to go to the backup specification level and you may need to decide to reschedule the backup run time.

It is basically a balancing act - you have X number of drives and you need to run Y number of backup sessions. You need to plan your backups so that you can equally allocate enough free drives for each of the backup specification.


Hope this helps

rgds,

Sherman

HPE DP SUPPORT

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Absent Member.. Gerasimov_Pavel Absent Member..
Absent Member..

Re: Drives allocation for specifications.

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Hello,

Thank you for reply but we have enough tape drives

we have 10 specifications starting at the same time, each specification use load balancing (min = 1/max = 1 drive) for each specification we allocate all 40 drives on the VTL. 

When specifications started they all choose first drive and 9 of 10 specifications  send us critical falure like busy drive.

As a result we have first ten drives permanently busy and rest of them stay free.  

Question is how to make them select them not the first drive but any drive available at random.

Best regards

Pavel

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Micro Focus Expert
Micro Focus Expert

Re: Drives allocation for specifications.

Jump to solution

The error message you get:

Cannot load exchanger medium (Target drive is busy.)"

is not related to drive but to the library robotics. DP is enough clever to not select drive one if already busy. You have an issue with the robotics control.

Have yo enabled lock on robotics ?

Probably you need also to change some robotics timeout to avoid it, but not having detailed info I cannot help. In any case it is correct to assign all 40 drive to the backup specification leaving to DP the chooice of which one to use. Dp will use the drive in the order you have selected in the backup specification. So if you have selected the entire library he will start from drive 1 to drive 40. If you want to change the allocation order select manually the drive in the order you like (i.e. start selecting from drive 40 backard). If you send the entire session log with the error may be we can help, otherwise run it in debug mode, open a support case and provide DP support the debug files.

Kind regards,

Dionisio

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