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EnhanceIO makes it possible to use an SSD as a caching device for any other type of block device storage (HDD, Network, you name it) with almost zero configuration. Based on Flashcache is it much simpler to set up. Unlike Bcache there is no need to convert file systems.

Warning: As always be careful and read the documentation carefully before attempting to use EnhanceIO, do not confuse your HDD and SDD and make sure the SSD does not have any important data on it.


Install enhanceio-dkms-gitAUR from the AUR.

Note: Throughout the page, /dev/sda will be used to indicate the slow drive and /dev/sdb will be used to indicate the fast drive. Be sure to change these examples to match your setup.

Setting up the module and drives

The EnhanceIO command line interface (eio_cli) is used to manage your setup. Set up caching on your fast ssd for your slow hdd like so:

# eio_cli create -d /dev/sda -s /dev/sdb -c my_first_enhanceio

This will use the default options which are safe, if you want to enhance speed even further you might want to add -m wb to enable WriteBack mode instead of WriteThrough. This might put data itegrity at risk though.

The cache drive is persistent now, which means even after a reboot it will still be used. If you want to deactive it first set the cache into read-only mode to not lose any yet unwritten blocks

# eio_cli edit -c my_first_enhanceio -m ro

Then wait until

$ grep nr_dirty /proc/enhanceio/enchanceio_test/stats

returns 0. Now all the blocks have been written to your slow hdd and it's safe to delete the caching device:

# eio_cli delete -c my_first_enhanceio

Getting information on caches

To get basic information on caches in use try

# eio_cli info

To get detailed information use

$ cat /proc/enhanceio/my_first_enhanceio/stats
Tip: After initiating EnhanceIO I felt that my system had become more sluggish, this seems to be due to building up the cache first. Use your system like you normally would and open up those applications you would want to start quickly, maybe give it another reboot and observe how things fly.