Common in Linux than a set of cache which stores frequently accessed pages on the server. If any data is requested by RAM, the configuration is set up so that the cache memory checks for available data and serves it from there. By doing this, servers can use their resources more efficiently and respond more quickly.
A Linux or Unix server’s cache/buffer memory can be flushed in different ways.
How to clear cache/buffer memory on a Linux server?
To clear page cache, directories & inodes i.e. flush all from the cache memory
sync; echo 3 > /proc/sys/vm/drop_caches
To clear only inodes anddirectories from the cache memory
sync; echo 2 > /proc/sys/vm/drop_caches
To clear only page cache from the cache memory
sync; echo 1 > /proc/sys/vm/drop_caches
How to set a cron job to clear cache memory in Linux?
It may be necessary to clear the cache memory and free up disk space at regular intervals. By using crontab, one can automatically clear the cache memory by creating a cron job.
Step 1:Access the Virtual Machine
Access the desired server through the shell as a root or sudo user.
Step 2:Create a shell script
Create a shell script lets say “clearcache.sh” under the root (/root) partition with following commands
!/bin/sh sync; echo 3 > /proc/sys/vm/drop_caches
Step 3:Set the permission
Set the permission of “clearcache.sh” script to 755
chmod 755 /root/clearcache.sh
Step 4:Edit the system crontab file
Edit the system crontab file using the below command
Step 5: Set cron jobs
Enter the following line in the crontab file to set cron job for clearing cache memory automatically
0 * * * * /root/clearcache.sh
The above cron job will execute the “clearcache.sh” script every hour of first second.
Step 6: Restart Crontab
Restart cron service
Note: One should be a root user or sudo user to perform the above-mentioned operations.
Is it necessary to remove cache memory from RAM periodically?
Well, it depends on the situation. Generally, it is not advisable to clear cache at regular intervals on production servers as this will force the server to serve by disk if the cache is not being built up, thus increasing the server’s load and resources.
Hopefully, after consulting this website, you will get a good understanding of the Linux cache.
Please let us know your feedback, queries by posting in the comment section.