DMP driver tunables
Prev Reference tables of Storage Foundation tunable parameters Next

DMP driver tunables

DMP uses a slab allocator to service I/Os. DMP uses the DMP driver tunables dmpslab_minsz and dmpslab_maxsz to control the memory allocated for this slab allocator. These tunables are defined as follows:

dmpslab_maxsz

Maximum size of the slab. The size is specified in pages, where 1 page equals 4096 bytes.

The default value for dmpslab_maxsz is 5% of the physical memory.

dmpslab_minsz

The minimum memory size that should be allocated to the slab during the driver load time. The size is specified in pages, where 1 page equals 4096 bytes.

The default value for dmpslab_mazsz is 24 pages.

To display the tunables, use the following command:

# lsattr -El vxdmp
dmpslab_maxsz   101580 N/A True
dmpslab_minsz   32     N/A True

Note:

If the errpt displays ENOMEM error code, you might need to change the dmpslab_minsz and dmpslab_maxsz to suit the load on the system.

Changing the value of the DMP driver tunables

  1. Specify a new size in pages. You must increase the size in multiples of 8.

    To change the dmpslab_minsz tunable:

    # chdev -P -l vxdmp -a dmpslab_minsz=newsize

    To change the dmpslab_maxsz tunable: 

    # chdev -P -l vxdmp -a dmpslab_maxsz=newsize
  2. Reboot the system for the new values to take effect.
Prev Up Next
DMP tunable parameters Home Tunable parameters for VxVM