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:

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!

Hardware/Driver file system required Linux kernel version required mount option Reference
SATA/libata ext3 ≥ 2.6.12 barrier=1 Jens Axboe, linux-scsi, 2005-07-01
SATA/libata reiserfs 3.6 ≥ 2.6.12 barrier=flush Jens Axboe, linux-scsi, 2005-07-01
ATA (traditional "IDE") ext3 ≥ 2.6.9 barrier=1 Jens Axboe, linux-scsi, 2005-07-02
ATA (traditional "IDE") reiserfs ≥ 2.6.9 barrier=flush Jens Axboe, linux-scsi, 2005-07-02

Matthias Andree