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Kernel Parameters Configuration - Linux MediaAgent

  • 13 September 2021
  • 6 replies
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According to the documentation, “If you are using an earlier version of the operating system, you can optimize the usage of these resources by setting the kernel parameter values” but, the documentation does not make it clear which versions to consider.

Does it apply to a Linux release 7.9.2009 (Core) (3.10.0-1160.42.2.el7.x86_64)?

And what about number_of_desired_streams?

SEMMSL = 12 * number_of_desired_streams

How to calculate the number of desired streams? Is it the sum of the values for Desired Streams from all the Associated Storage Policies? 

 

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Best answer by Gowri Shankar 17 September 2021, 23:19

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Userlevel 2
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Yes, thats right.

For a MA calculate for 100 additional streams, in total 300 streams 

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Will be a very good idea to open a ticket with Commvault Support and discuss/review with them first what are the best recommended things to be modified there, since they sometime use some safe values, but usually those values are dependent on multiple parameters who may differ: environment / your need. I guess as best approach, have a discussion first with support and try to follow support recommendation’s. We all know, that documentations, it’s not always complete and/or updated.

Userlevel 7
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FYI, @Gowri Shankar is not only in support, he’s the Unix support Associate Manager.  I made sure to recruit the big guns!

Userlevel 2
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Hi @Eduardo Braga, Yes this is applicable for all the versions of Linux.

 

The total number of desired streams per media agent can be found from the Storage resources → Media Agent → Media Agent properties 

 

An example can be found here

 

  1. mportant Considerations

    • The minimum recommended value for the SEMMNI parameter is 128 (non-MediaAgent) and 512 (MediaAgent).

    • Use the following formula to calculate the value for the SEMMSL parameter:

      • Non-MediaAgent:

        SEMMSL = 1 * number_of_desired_streams

      • MediaAgent:

        SEMMSL = 12 * number_of_desired_streams

    • Use the following formula to calculate the value for the SEMMNS parameter:

      SEMMNS = SEMMSL * SEMMNI

    • The SEMOPM and SEMMSL parameter values must be equal.

    • If any applications or databases are running on the client, the parameters must be increased accordingly.

Example

Parameters

Non-MediaAgent

MediaAgent

SEMMSL

1 * 250 = 250

12 * 100 = 1200

SEMMNI

128

512

SEMMNS

250 * 128

1200 * 512

SEMOPM

250

1200

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Hi @Eduardo Braga, Yes this is applicable for all the versions of Linux.

 

The total number of desired streams per media agent can be found from the Storage resources → Media Agent → Media Agent properties 

 

An example can be found here

 

  1. mportant Considerations

    • The minimum recommended value for the SEMMNI parameter is 128 (non-MediaAgent) and 512 (MediaAgent).

    • Use the following formula to calculate the value for the SEMMSL parameter:

      • Non-MediaAgent:

        SEMMSL = 1 * number_of_desired_streams

      • MediaAgent:

        SEMMSL = 12 * number_of_desired_streams

    • Use the following formula to calculate the value for the SEMMNS parameter:

      SEMMNS = SEMMSL * SEMMNI

    • The SEMOPM and SEMMSL parameter values must be equal.

    • If any applications or databases are running on the client, the parameters must be increased accordingly.

Example

Parameters

Non-MediaAgent

MediaAgent

SEMMSL

1 * 250 = 250

12 * 100 = 1200

SEMMNI

128

512

SEMMNS

250 * 128

1200 * 512

SEMOPM

250

1200

 

@Gowri Shankar Do you mean “Maximum Number of parallel data transfer operations”? 

 

 

Userlevel 7
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Hey @Eduardo Braga , let me get an answer (and a doc update) for you!

I’ll reach out to our internal people who handle these items and either reply back or have them do so.

Thanks!

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