Data Domain: Alert Calculation for Space in file "ddvar"

Summary: Alert Calculation for Space in /ddvar.

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Instructions

Alert Calculation for Space in /ddvar

SYMPTOMS

An alert is generated that states:  

Space running low in /ddvar  when the space used percentage appears to be low.

APPLIES TO

  • All Data Domain systems
  • All Software Releases

PURPOSE

This article explains the calculation used to send the space running low in /ddvar alert even though /ddvar space usage is at a low percentage.

CAUSE

The /ddvar alert is triggered based on the amount of RAM in relation to the space available in /ddvar. A further explanation of the calculation is provided below.

SOLUTION

The first /ddvar warning is triggered when:

ddvar_space_available <= RAM_size + 3 GiB

The second warning is triggered when:

ddvar_space_available < RAM_size + 1 GiB

Example:
The following system received the alert that the space running low in /ddvar, but /ddvar is only displaying 63% full.

Resource             Size GiB   Used GiB   Avail GiB   Use%   Cleanable GiB

------------------   --------   --------   ---------   ----   -------------

/backup: pre-comp           -    26946.1           -      -               -

/backup: post-comp     2449.2     1112.4      1336.8    45%            42.8

/ddvar                   19.7       11.8         6.9    63%               -

------------------   --------   --------   ---------   ----   -------------  

# system show meminfo

System Memory Summary

---------------------

Memory Usage Summary

Total memory:   3930 MiB

Free memory:    56 MiB 

Total swap:     4095 MiB

Free swap:      4091 MiB

The available space in /ddvar is 6.9 GB and that the amount of RAM (Total memory) is 4 GB. If this is plugged into the calculation, the total space between RAM and available space in /ddvar is 7.0 GB. Since this is greater than 6.9 GB, the alert is generated.

6.9 Avail in ddvar <= 4 GiB of RAM + 3 GiB 6.9 < 7 = Alert

To clear the alert, you must clean up the /ddvar directory. See article Data Domain - Space Running Low in /ddvar.

Changes as of DD OS 5.4

The algorithm for calculating space needed for cores has changed in DD OS 5.4 due to the following:

  • Kernel cores now require up to 10 Gb of storage
  • DDFS cores require up to 40% of the total RAM size
  • Miscellaneous cores require up to 5 Gb

New alert standards:

  • Issue a warning alert when space in /ddvar falls below total of the above values
  • Issue a cores disabled alert when space in /ddvar falls below 1/2 of total of above values

REFERENCE

Additional Information

 

    Affected Products

    Data Domain

    Products

    Data Domain
    Article Properties
    Article Number: 000012119
    Article Type: How To
    Last Modified: 19 Sep 2025
    Version:  4
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