There are three options available to flush cache of Linux memory. Use one of below as per your requirements.
- Free pagecache, dentries and inodes in cache memory
# sync; echo 3 > /proc/sys/vm/drop_caches
- Free dentries and inodes use following command
# sync; echo 2 > /proc/sys/vm/drop_caches
- Free pagecache only use following command
# sync; echo 1 > /proc/sys/vm/drop_caches
Schedule Cron to Flush Cache Regularly
Its a good idea to schedule following in crontab to automatically flush cache on regular interval.
# crontab -l 0 * * * * sync; echo 3 > /proc/sys/vm/drop_caches
The above cron will execute on every hour and flushes the cached memory on system.
Find Cache Memory uses in Linux
Use free command to find out cache memory uses by Linux system. Output of free command is like below
# free -m -h
Sample Output
total used free shared buffers cached Mem: 16050 15908 142 0 120 14953 -/+ buffers/cache: 834 15216 Swap: 0 0 0
Last column is showing cached memory ( 14953 MB) by system. -m option is used for showing memory details in MB’s and -h is human readable