rotatelogs is a simple program for use in conjunction with Apache's piped logfile feature. It supports rotation based on a time interval or maximum size of the log.
Causes the use of local time rather than GMT as the base for the interval or for strftime(3) formatting with size-based rotation. Note that using -l in an environment which changes the GMT offset (such as for BST or DST) can lead to unpredictable results!
Causes the logfile to be opened immediately, as soon as rotatelogs starts, instead of waiting for the first logfile entry to be read (for non-busy sites, there may be a substantial delay between when the server is started and when the first request is handled, meaning that the associated logfile does not "exist" until then, which causes problems from some automated logging tools). Available in version 2.2.9 and later.
The path plus basename of the logfile. If logfile includes any '%' characters, it is treated as a format string for strftime(3). Otherwise, the suffix .nnnnnnnnnn is automatically added and is the time in seconds. Both formats compute the start time from the beginning of the current period. For example, if a rotation time of 86400 is specified, the hour, minute, and second fields created from the strftime(3) format will all be zero, referring to the beginning of the current 24-hour period (midnight).
The time between log file rotations in seconds. The rotation occurs at the beginning of this interval. For example, if the rotation time is 3600, the log file will be rotated at the beginning of every hour; if the rotation time is 86400, the log file will be rotated every night at midnight. (If no data is logged during an interval, no file will be created.)
The maximum file size in megabytes followed by the letter M to specify size rather than time.
The number of minutes offset from UTC. If omitted, zero is assumed and UTC is used. For example, to use local time in the zone UTC -5 hours, specify a value of -300 for this argument. In most cases, -l should be used instead of specifying an offset.
CustomLog "|bin/rotatelogs /var/logs/logfile 86400" common
This creates the files /var/logs/logfile.nnnn where nnnn is the system time at which the log nominally starts (this time will always be a multiple of the rotation time, so you can synchronize cron scripts with it). At the end of each rotation time (here after 24 hours) a new log is started.
CustomLog "|bin/rotatelogs -l /var/logs/logfile.%Y.%m.%d 86400" common
This creates the files /var/logs/logfile.yyyy.mm.dd where yyyy is the year, mm is the month, and dd is the day of the month. Logging will switch to a new file every day at midnight, local time.
CustomLog "|bin/rotatelogs /var/logs/logfile 5M" common
This configuration will rotate the logfile whenever it reaches a size of 5 megabytes.