Moving to a new SSD drive would be best recommendation.
To do this, you will need to do a new install. This will not affect your data, but you will need to schedule a maintenance window to do so, as well as stop cluster services.
Download and save the settings and configuration from the webGUI. MAINTENANCE-->Miscellaneous.
Note down your product key from HELP-->About.
Perform a new install to SSD from either cd rom, or usb installer, instructions can be found here: http://www.open-e.com/download/manuals-and-quickstarts/
Once install is complete, configure the management IP from the console screen (CNTRL+ALT+N).
Connect to the webGUI and enter your product key, reboot
After reboot, you may restore the previously saved settings and configuration in the webGUI, reboot.
Do this on each system, and restart the cluster after.