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Media Multiplexing

Hello Experts,

We have set Media Multiplexing value 4 in policy and in storage unit it is set as 16. I ran nbrbutil -listActiveDrivejobs Drive001 and found there are 5 jobs running. Then i checked in other drives and found all are drives are writing 5 jobs.

So i need to know why these are 5 jobs not 4 as we have set Multiplexing as 4 in policy.

Thanks,

 

1 Solution

Accepted Solutions
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Accepted Solution!

You need to have a look at

You need to have a look at MPX in schedules of ALL policies. (So far you have mentioned policy (which means only one policy to me).)
You say above: these 5 jobs are from differnt policies.

We also need to know ho many active jobs - bpbdbjobs |grep -i active (not just amount of active drives).

If there are 5 clients, there will be a minimum of 5 active jobs for the one policy. One per client. 
MPX will make more than one job go to the same drive, not have less jobs.
Now you also need to look at the policies of the other active jobs.

If 1 policy has MPX of 1 and another policy has mpx of 4, then the lowest value (1) will override the higher value.
Same for schedule mpx and STU mpx - the lower level overrides the higher level.

Other factors that play a role is the volume pool specified in the policies and retention levels in the schedules of the different policies.

Have a careful look at these 2 links:

About Multiplexing: http://www.symantec.com/docs/HOWTO86804 

Example of using multiplexing with schedule: http://www.symantec.com/docs/HOWTO86888 

Hopefully comparing the diagrams in above URLs with your own config and active jobs vs active tape drives seen in your environment will help to clear any doubts.

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16 Replies
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Another policy running

Another policy running perhaps?   Try this command:

bpdbjobs | findstr "Active"

 

 

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there are 3 different

there are 3 different policy...

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OK, so you enable multiple

OK, so you enable multiple streams in the policy, and set an MPX value in the schedule. Did you enable mpx in the storage unit as well ?
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Limit Storage unit

Limit Storage unit multiplexing maximum strem per drive to 4 to fix this issue
 

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Hi Martin, In Policy its =

Hi Martin,

In Policy its = 4 

 Storage unit:- 

Maximum concurrent write drives= 8

Multiplexing Enabled with 16 Maximum streams per drive.

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In the schedule for the

In the schedule for the policy, is there are setting "Media multiplexing" (bottom right of window), what is this set to, if it's 1, make it 4

You could reduce the MPX enabled with 16 streams down to 4, but I don;t think that is causing the issue, should work at 16.

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What is 'Max Jobs Per Client'

What is 'Max Jobs Per Client' set to in Global Attributes of Master server Host Properties?

Have you enabled 'Allow Multiple data streams' in Policy Attributes?

Any Max Jobs limit in Policy Attributes?

How many Clients in this Policy?

What is in Backup Selection tab?

All of these will play a role in amount of jobs that get activated and multiplexing/multistreaming.

If you show us your policy config, we can tell you how many jobs to expect per drive:
bppllist <policy-name> -U.

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Hi Marianne 1:- Max job per

Hi Marianne

1:- Max job per client:- 15

2:- No Data Streams.

3:- Default Unlimited.

4:- 5 Clients

5:- Flat Files.

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Please post Output of

Please post Output of bppllist <policy-name> -U and bpstulist -verbose -U. Also you could check the job details of those 5 jobs and post it here, it will clearly tell the information.

Post all this infromation.

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Okay - 5 drives writing 5

Okay - 5 drives writing 5 jobs?
One job per client in the policy, right?

Can we assume the MPX in the schedule was previously 1?

How long after chanching MPX to 4 in the schedule did you start the job?

Please bear in mind that the NBU scheduler (nbpem) only checks for policy updates every 10 minutes.

So, if you change anything in the policy, follow up with refresh of nbpem:

nbpemreq -updatepolicies

Experience has told me that even this command does not always work and best to wait out the 10 minutes.

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Hi Marianne, Let me repharse

Hi Marianne,

Let me repharse my question.

We have 8 Drives....

1:- In Storage Unit
Maximum Concurrent Write Drives = 8
Maximum Streams per drive = 16

2:-In Policy

A:- schedules:-Attribute
Media Multiplexing = 4

B:- Limit Jobs per policy = Unlimited

3:-In Host Properties

Master Server
Global Attibutes 
Maximum Jobs per client =30 

4:- Policy has 5 Clients

If i run nbruutil -listActiveDrivejobs its showing me 5 jobs But 

these 5 jobs are from differnt policies in the drive 1 and same is happening in other drives as well.
So i have two queries.

1:- Why are there 5 jobs not 4.?
2:- Whats needs to be done to increase it as we are using LT0-6 Tapes.?

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What is the mpx value in the

What is the mpx value in the schedule for the policy

Highlighted
Accepted Solution!

You need to have a look at

You need to have a look at MPX in schedules of ALL policies. (So far you have mentioned policy (which means only one policy to me).)
You say above: these 5 jobs are from differnt policies.

We also need to know ho many active jobs - bpbdbjobs |grep -i active (not just amount of active drives).

If there are 5 clients, there will be a minimum of 5 active jobs for the one policy. One per client. 
MPX will make more than one job go to the same drive, not have less jobs.
Now you also need to look at the policies of the other active jobs.

If 1 policy has MPX of 1 and another policy has mpx of 4, then the lowest value (1) will override the higher value.
Same for schedule mpx and STU mpx - the lower level overrides the higher level.

Other factors that play a role is the volume pool specified in the policies and retention levels in the schedules of the different policies.

Have a careful look at these 2 links:

About Multiplexing: http://www.symantec.com/docs/HOWTO86804 

Example of using multiplexing with schedule: http://www.symantec.com/docs/HOWTO86888 

Hopefully comparing the diagrams in above URLs with your own config and active jobs vs active tape drives seen in your environment will help to clear any doubts.

View solution in original post

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Hi MPH its 4

Hi MPH

its 4

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I was hoping that you would

I was hoping that you would also reply to my post below.....

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Hi Marianne, I was missing

Hi Marianne,

I was missing retention level. Thanks so much