How to Clear Memory Cache in Linux

Linux Systems have three options to clear cache without interrupting any processes or services. Follow the steps how to clear memory cache in Linux.

1. Clear PageCache Only

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

• What it does: Frees page cache (cached files).
• Use case: When you want to clear cached file data.

2. Clear Dentries and Inodes

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

• What it does: Frees dentries (directory entries) and inodes (file metadata).
• Use case: When you want to clear metadata, but not the actual cached files.

3. Clear PageCache, Dentries, and Inodes

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

• What it does: Frees page cache, dentries, and inodes.
• Use case: When you want to clear everything cache-related.

Important Notes:

• Always run sync before clearing cache to make sure all cached data is written to disk, preventing potential data loss.
• You need root privileges to execute these commands. Use sudo if you are not logged in as root:bashsudo sh -c ‘sync; echo 3 > /proc/sys/vm/drop_caches’
• This is generally safe, but clearing the cache might slow down your system temporarily as it will need to reload files into memory.

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