Which combinations of Linux kernel, hardware, file system and mount options are safe to use?

$Date: 2005/07/03 17:18:25 $

Enabling hard disks' write caches is dangerous, as it often breaks assumptions that the Linux kernel makes WRT write ordering. Unfortunately, many disk drives ship with the write cache enabled, to improve MTBF (by reducing seeks) and performance. The consequence is often file system corruption when a power failure (mains power, UPS or power supply unit failing, flakey cables and so on) occurs with writes pending or in progress.

For any combination not listed below, disable the write cache:

• For IDE drives, use hdparm -W0 /dev/DEVICE.
• For SCSI drives, use scsi-config and remember to save settings.
• For SATA and RAID, information is needed.

This page comes without warranties. In doubt, disable write caches and see if performance is still acceptable.
Note that with the write cache disabled, the mean time between failures (MTBF) may be reduced!