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vio_daemon consuming high memory on VIOS

Technote (FAQ)


Question

Why is vio_daemon consuming high memory on PoweVM Virtual I/O Server (VIOS)?

Cause

The problem can be due to a known issue in VIOS 2.2.3.0 thru 2.2.3.3 with vio_daemon having a memory leak that was fixed at 2.2.3.4 with IV64508, or it could be due to incorrect VIOS settings.

Answer

To check your VIOS level, as padmin, run:
$ ioslevel

If your VIOS level is 2.2.3.4 or higher, the problem may be due to the VIOS having incorrect system settings in /etc/security/limits. If the "stack" size is set to "unlimited" (stack = -1), this exposes a condition where the system can be allowed to pin as much stack as desired causing vio_daemon to consume a lot of memory.

$ oem_setup_env

# vi /etc/security/limits ->check the default stanza

default:
        fsize = -1
        core = -1
        cpu = -1
        data = -1
        rss = -1
        stack = -1
        nofiles = -1

In some cases, the issue with vio_daemon consuming high memory is noticed after a VIOS update to 2.2.3.X. However, a VIOS update will NOT change these settings. It is strongly recommended not to modify these default values as doing so is known to cause unpredictable results. Below is an example of the default values:

default:
        fsize = 2097151
        core = 2097151
        cpu = -1
        data = 262144
        rss = 65536
        stack = 65536
        nofiles = 2000


To correct the problem change the setting back to "default" values. Then reboot the VIOS at your earliest convenience.


    Note 1
    If the stack size was added to the root and/or padmin stanzas with unlimited setting, it should be removed prior to rebooting the VIOS.

    Note 2
    If the clients are not redundant via a second VIOS, a maintenance window should be schedule to bring the clients down before rebooting the VIOS.


Last, if your environment does not meet the above criteria, gather the following data to better ascertain if vio_chgmgt is reaching a limit in /etc/security/limits configuration or some other leak. Then contact your local SupportLine Representative and provide the testcase.

Document information

More support for: Virtual I/O Server

Software version: 2.2.3.0

Operating system(s): Other

Software edition: Enterprise, Express, Standard

Reference #: T1022976

Modified date: 26 April 2016