BUFSIZMAX, BUFUSEWARN, DSPSIZMAX, PERMFIX, and NOBUFFS — Specifying SMF buffer options

You can use the BUFSIZMAX, BUFUSEWARN, DSPSIZMAX, Start of change

PERMFIX

, and NOBUFFS parameters to specify SMF buffering options. Note how these parameters apply:

BUFUSEWARN and NOBUFFS apply to SMF log streams and data sets
BUFSIZMAX applies to data set record
DSPSIZMAX and PERMFIX applies to logstream recording

The BUFSIZMAX parameter specifies the maximum amount of storage that SMF can allocate for buffering purposes. The value of BUFSIZMAX can range from a minimum of 128M to a maximum of 1G. The default value of BUFSIZMAX is 128M.

The DSPSIZMAX parameter specifies the maximum amount of storage that SMF can use for a given SMF logstream's buffer. The value of DSPSIZMAX can range from a minimum of 128M to a maximum of 2G. The default value is 2G.

The BUFUSEWARN parameter specifies the overall buffer warning level percentage which, when exceeded, causes SMF to start issuing message IEE986E. The value of BUFUSEWARN can range from 10 to 90 percent; the default value being 25 percent. When the overall SMF buffer in use percentage drops below the specified BUFUSEWARN value, SMF issues DOM message IEE986E.

Start of change The PERMFIX parameter specifies the default amount of storage SMF can keep permanently fixed for each log stream for purposes of communicating with the zEDC Express® feature. Storage used by the zEDC Express feature must be page fixed; however, fixed pages are a constrained resource. Increasing this number can improve performance of SMF, but decrease the fixed storage available to the other applications. Decreasing this number can increase the fixed storage available to other applications, but may degrade SMF performance. PERMFIX can range from a minimum of 1M to a maximum of 2GB. The default value is NOPERMFIX. Due to processing needs, even if this value is NOPERMFIX, SMF may use up to 2MB of fixed storage for zEDC usage. End of change

You can specify NOBUFFS, BUFUSEWARN, Start of change PERMFIX End of change , and DSPSIZMAX on the LSNAME and DEFAULTLSNAME keywords. The global NOBUFFS, BUFUSEWARN and DSPSIZMAX values are applied to any logstream that does not have any of the options specified.

DEFAULTLSNAME(logstreamname,
NOBUFFS(MSG|HALT),
BUFUSEWARN(nn),
DSPSIZMAX(nnnnM | nG))
PERMFIX(nnnnM)
LSNAME(logstreamname,
TYPE({aa,bb}|{aa,bb:zz}|{aa,bb:zz,..}),
NOBUFFS(MSG|HALT),
BUFUSEWARN(nn),
DSPSIZMAX(nnnnM | nG))
PERMFIX(nnnnM)

You can use the combination of BUFSIZMAX and BUFUSEWARN parameters to prevent SMF data loss conditions (see Preserving SMF Data).

After setting the SMF buffer options, if you still cannot prevent data loss conditions, use the SMF NOBUFFS parameter (see Using SMFPRMxx parameters), to specify what the system is to do in this situation. The following are the possible system actions:

Continue processing with the loss of SMF data and if parmlib option NOBUFFS(MSG) is in effect, message IEE979W will be issued. All records presented to SMF will be lost until buffers become available. When no buffers are available for a given SMF log stream and the NOBUFFS(MSG) action is specified, message IFA786W will be issued. SMF records have been lost and more might be lost until SMF can write the buffered records to the SMF log stream.
Enter a restartable wait state.
Note: When the BUFSIZMAX parameter is specified, if the amount of storage requested is not available during initialization, SMF will take the specified value and decrease it by 20% and attempt to get that amount. If unsuccessful, SMF will retry this 4 additional times. Message IFA723E will be issued with the amount of storage which SMF was finally able to obtain.
When the BUFSIZMAX parameter is specified by using a SETSMF or SET SMF=xx command, if the new larger area cannot be obtained, the current value will remain in effect. Message IFA723E will be issued to the console where the SETSMF or SET SMF=xx command was entered.