How to Clear Cache Memory

            Linux has implemented a memory management efficiently.If any process is eating away your memory and you want to clear it.Linux provides a way to flush or clear ram cache.

            Every Linux System has three options to clear cache without interrupting or services.

1.Clear PageCache Only.

# sync; echo 1 > /proc/sys/vm/drop_caches

2.Clear dentries and inodes.

# sync; echo 2 > /proc/sys/vm/drop_caches

3.Clear Pagecache,dentries and inodes.

# sync; echo 3 > /proc/sys/vm/drop_caches

Explain above command

        Sync will flush the file system buffer.Command Separated by “;” run sequentially.The Shell wait for each command to terminate before executing the next command in the sequence.drop_cache will clean cache without killing any application/service.echo is doing the job of writing to file

       Now we will create a shell script to auto clear RAM cache daily at 2am via cron scheduler task.Create a shell script clearcache.sh and add the following lines.

#!/bin/bash
# Note, we are using "echo 3", but it is not recommended in production instead use "echo 1"
echo "echo 3 > /proc/sys/vm/drop_caches"

Set execute permission on the clearcache.sh file.

# chmod 755 clearcache.sh

Now you may call the script whenever you requires to clear ram cache
Now set a cron to clear RAM cache everyday at 2am.Open crontab for editing

# crontab -e

Append the bellow line,save and exit to run it at 2am daily

0  2  *  *  *  /path/to/clearcache.sh

For more details on How to cron a job