log file rotation setting

Question

It is a bit weird that in my /var/log dir, many files such as syslog, auth.log all seem to have older log files (rotated by [0-9], some like dpkg.log even rotates to 12 now), but the important wtmp log file only has a wtmp.1 rotation, which stores pretty recent log (I have been using the laptop for several years, so in normal case it should have more wtmp logs).

Is it because of some system setting that prevents my laptop from storing more wtmp logs? (I do not recall that I changed the default setting for this.)

Thank you.

Answer 1

You just need to edit the /etc/logrotate.conf file:

sudo gedit /etc/logrotate.conf

Mine by default looks like this:

# see "man logrotate" for details
# rotate log files weekly
weekly

# keep 4 weeks worth of backlogs
rotate 4

# create new (empty) log files after rotating old ones
create

# uncomment this if you want your log files compressed
#compress

# packages drop log rotation information into this directory
include /etc/logrotate.d

# no packages own wtmp, or btmp -- we'll rotate them here
/var/log/wtmp {
    missingok
    monthly
    create 0664 root utmp
    rotate 1
}

/var/log/btmp {
    missingok
    monthly
    create 0660 root utmp
    rotate 1
}

# system-specific logs may be configured here

All you have to do is changing:

/var/log/wtmp {
    missingok
    monthly
    create 0664 root utmp
    rotate 1  <------ change this value to 12 to keep log files for 12 months
}

by

/var/log/wtmp {
    missingok
    monthly
    create 0664 root utmp
    rotate 12
}

to keep log files for 12 months.