On Dec 23, 2010, at 2:12 AM, cpolish at surewest.net wrote: > Matt wrote: >> Is ext4 stable on CentOS 5.5 64bit? I have an email server with a >> great deal of disk i/o and was wandering if ext4 would be better then >> ext3 for it? > > Before committing to ext4 on a production server, it > would be good to consider the comments made in > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/317781/comments/45 > which presumably still apply to current CentOS 5.5 64-bit kernels. > As I read it, Ts'o argues that the apparent loss of stability > compared to ext3 is a design issue in the realm of applications > that run atop it. I hope this is not a misreading. Waiting for applications to be properly written, ie use fsync(), is no way to pick a file system. You'd have the same problems on xfs or any other file system that does delayed writes. It was only a side-effect of ext3's journal=ordered that caused it to flush dirty pages every 5 seconds. If that's what you want then you can use sysctl to tune vm to flush every 5 seconds and that will cover all delayed write file systems. -Ross