cblock exhaustion

[Nantambu Starks]

Does anyone know what causes and what fixes an error that is showing up in my syslog.log: "vmunix: WARNING: cblock exhaustion has occured" I am seeing processes running abmormally high on my system and I have an idle of 0%

[Stephen Keane]

You may need to increase your kernel parameter

nclist

[Govinda_1 · Accepted solution]

hi,

just check this thread, which may help you.

http://docs.hp.com/en/B3921-90010/nclist.5.html

regards,
Govind.

[harry d brown jr]

you probably need to increase the kernel parameter "nclist":

FROM SAM (gui version)/kernel configuration/Configurable parameters/help

nclist
Specify number of cblocks for pty and tty data transfers.
Acceptable Values:

Minimum: 132
Maximum: Limited by available memory
Default: (100 + 16 * MAXUSERS)

Specify integer value or use integer formula expression. For more information, see Specifying Parameter Values.
Description
nclist specifies how many cblocks are allocated in the system. Data traffic is stored in cblocks as it passes through tty and pty devices.

The default value for nclist, (100 + 16 * MAXUSERS), is based on a formula of 100 cblocks for system use in handling traffic to the console, etc., plus
an average of 16 cblocks per user session. Note that cblocks are also used for serial connections other than login sessions, such as as SLIP
connections, UUCP transfers, terminal emulators, and such. If your system is using these other kinds of connections, nclist should be increased
accordingly.

If the cblock pool is exhausted, data being passed through a tty or pty device might be lost because no cblock was available when it was needed. If this
occurs, the following message is placed in the system message buffer:

WARNING: cblock exhaustion has occurred n times (see termio(7)).

This indicates that nclist needs to be increased. The minimum value for nclist is 132. There is no maximum, but each cblock consumes 32 bytes of
resident (non-swappable) machine memory, so the value should be selected with this in mind.
Additional Information

* Overview of Miscellaneous Parameters

* List of parameters

* Browse configurable kernel parameters help
live free or die
harry d brown jr

[Nantambu Starks]

Thanks for all the help guys

[Nantambu Starks]

I received great information on cblock exhaustion/ nclist kernel parameter from some of the forums more experienced HP-UX users