You can, if necessary, increase the number of log data sets available for log streams using the DSEXTENT parameter in the LOGR couple data set. If you have log streams that will exceed 168 DASD log data sets, perhaps because you retain data in your log stream for a long period of time, increase the number of directory extents available for the sysplex on the DSEXTENT parameter in the LOGR couple data set using the format utility (see Format utility for couple data sets). Each additional directory extent specified goes into a common pool available to any log stream in the sysplex. System logger allocates these directory extents as needed. Each directory extent allows a log stream to extend beyond 168 log data sets. Whenever all the log data sets in a data set directory extent have been physically deleted, system logger returns the directory extent record to the available pool of directory extents for the sysplex. Each log stream has one data set directory extent which is part of the log stream record, not part of the data set directory extent pool. This permanent directory extent is always used first for a log stream, before retrieving a directory extent from the common data set directory pool. This permanent extent does not revert to the common pool when unused and is not available for use by any other log stream - it is held for the owning log stream.

To specify additional extents, format a LOGR couple data set with additional directory extents on the DSEXTENT parameter. Then make that LOGR couple data set available as the active primary (see Format the LOGR couple data set and make it available to the sysplex).

If you are not using DSEXTENT in the LOGR couple data set, the data set directory limit for a log stream is 168 data sets. (Note that your DASD staging data sets do not count toward the 168 limit.) If you reach the data set directory limit for a log stream, system logger will not be able to offload data.

You can make additional directory space available for a log stream by deleting log data from the log stream. (See Deleting log data and log data sets.) Whenever the number of log data sets in use gets above 90% of the total number allowed (168), the system logger issues message, IXG257I. This message will be deleted when either the number of log data sets for the log stream drops below 85% of the total allowed or the last connection to the log stream in the sysplex disconnects. In the latter case, the message will be reissued if an application reconnects to the log stream.

Whether or not you use DSEXTENT to increase the number of log data set directory extents for a log stream, you can also set up a retention period and automatic deletion policy for a log stream to ensure that your log streams will not run out of directory space. See Managing log data: How much? For how long?.