Emptying the buffers cache - Servers24 Cloud

If you ever want to empty it you can use this chain of commands.

You can signal the Linux Kernel to drop various aspects of cached items by changing the numeric argument to the above command.

To free pagecache:
```
# echo 1 > /proc/sys/vm/drop_caches
```
To free dentries and inodes:
```
# echo 2 > /proc/sys/vm/drop_caches
```
To free pagecache, dentries and inodes:
```
# echo 3 > /proc/sys/vm/drop_caches
```
The above are meant to be run as root. If you're trying to do them using sudo then you'll need to change the syntax slightly to something like these:
```
$ sudo sh -c 'echo 1 >/proc/sys/vm/drop_caches'
$ sudo sh -c 'echo 2 >/proc/sys/vm/drop_caches'
$ sudo sh -c 'echo 3 >/proc/sys/vm/drop_caches'
```
NOTE: There's a more esoteric version of the above command if you're into that:
```
$ echo "echo 1 > /proc/sys/vm/drop_caches" | sudo sh
```
Why the change in syntax? The /bin/echo program is running as root, because of sudo, but the shell that's redirecting echo's output to the root-only file is still running as you. Your current shell does the redirection before sudo starts.

Now we will be creating a shell script to auto clear RAM cache daily at 3 am via a cron scheduler task. Create a shell script clearramcache.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 1 > /proc/sys/vm/drop_caches"

Set execute permission on the clearramcache.sh file.

# chmod 755 clearcache.sh

Now you may call the script whenever you are required to clear the ram cache.

Now set a cron to clear RAM cache every day at 2 am. Open crontab for editing.

# crontab -e

Append the below line, save and exit to run it at 3 am daily.

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