Why is lastlog so huge?
Answer. The file is a sparse file and is not actually taking up as much physical space as it shows. lastlog records the last login of each user. The large size merely shows you the potential size of the file if there were a maximum amount of users (around 2^32 users).
Why is lastlog a sparse file?
/var/log/lastlog is a binary file that holds information about the last time that users logged in to the system. The lastlog file is a sparse file, which means that the apparent size reported by “ls -l” is larger than the actual disk usage of the file(du), because not all blocks in the file are allocated on disk.
What is the lastlog file in Linux?
/var/log/lastlog
lastlog is a program available on most Linux distributions. It formats and prints the contents of the last login log file, /var/log/lastlog (which is a usually a very sparse file), including the login name, port, and last login date and time.
What is lastlog in var log?
The /var/log/lastlog file is used to store information about the successful logins to the host. On several versions of RedHat Enterprise Linux and Fedora, corruption in this file can cause the size to be misrepresented. This has no effect on the real space used by the file, as reported by the du command.
Can Lastlog be deleted?
Task: Clear last login information by deleting /var/log/lastlog. Press CTR+D to save the changes.
What is sparse file in Windows?
A sparse file is a file with one or more regions of unallocated data in it. A program sees these unallocated regions as containing bytes with a zero value and that there’s no disk space representing these zeros. Sparse file support allows data to be deallocated from anywhere in the file.
Can I remove Lastlog in Linux?
What is BTMP file?
From Wikipedia, the free encyclopedia. utmp, wtmp, btmp and variants such as utmpx, wtmpx and btmpx are files on Unix-like systems that keep track of all logins and logouts to the system.
What is wtmp file?
Wtmp is a file on the Linux, Solaris, and BSD operating systems that keeps a history of all logins and logouts. On Linux systems, it is located at /var/log/wtmp. Various commands access wtmp to report login statistics, including the who and lastb commands. Log, Operating system, Operating System terms.
How do you purge Lastlog?
Linux Remove or Clear the Last Login Information
- lastlog command. The lastlog command shows the most recent login of all users or of a given user.
- Task: Display last login information. Simply type the lastlog command :
- Task: Clear last login information by deleting /var/log/lastlog.
- last and lastb commands.
What do Lastlog and Lastb commands do?
On the Linux systems there are three standard commands that show the information about last logged in users: last , lastb , and lastlog . The output of these commands include: login-name, last login time, IP address, port etc. And sometimes, to keep anonymity, it is required to erase last login history.
How do I check the size of a file in sparse?
Finding sparse files
- Use find command with “%S” to find each file’s sparseness.
- Value displayed in the leftmost column is (BLOCK-SIZE*st_blocks / st_size) which is normally less than 1.0 in case of sparse file.
How big is the lastlog file size in GB?
The partition is 4G (/var/log), however ls -lh /var/log/lastlog believes it is 465GB (four hundred and sixty-five GB). However, a df -PhT /var/log shows only 65M (sixty-five MB) being actually used. The /var/log is on an xfs local file system.
How big is the lastlog partition in Red Hat?
The partition is 4G (/var/log), however ls -lh /var/log/lastlog believes it is 465GB (four hundred and sixty-five GB). However, a df -PhT /var/log shows only 65M (sixty-five MB) being actually used.
What is a lastlog file in Windows 10?
That file is a log for sessions on your system, and you examine it by using lastlog. Every time a users login/logout from your system, the file is updated. You should ensure that the file is included in your “logrotate” configuration and that “logrotate” is enabled.