For devices without write caches, or with battery-backed write caches, you disable barriers using the This option allows you to set priority of I/O operations submitted during a commit operation.The option can have a value from 7 to 0 (0 is the highest priority), and is set to 3 by default, which is slightly higher priority than the default I/O priority.

updating to ext4-2

For more information on ext4, check out this overview of the extended (ext) file system from IBM Developerworks, including a short introduction on the history of Linux file systems.

Make sure you scroll to the end for a great list of ext4 resources.

Using an ext4 compatible bootloader Every time you power up a computer you go through a boot process involving first the BIOS and typically the boot sector on a hard disk.

For Linux systems the next step in the process involves either LILO (LInux LOader) or GRUB (GRand Unified Bootloader).

Ubuntu 9.10 also supports ext4 on the boot partition but requires you to run the grub-install command after an in-place upgrade (see the Ubuntu 9.10 release notes).

You should be aware that if you don't run the grub-install you will find yourself with an unusable system.File system decisions Migrating existing Linux volumes to ext4 should be evaluated on a case-by-case basis.If you need the support for large files ( 16 TB) or numbers of sub directories (ext3 is limited to 32000) you'll definitely want to upgrade.With ext4, it is possible to skip over inodes that are known to be empty.Performance improvements by over 100% have been seen in some ext4 benchmarks performed for the Linux Foundation.You can also turn journaling off if you don't need the extra reliability and need the performance gain.