On 12/23/2010 9:08 AM, Ross Walker wrote: > 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. But note that the reason applications don't use fsync() when they should is probably due to linux historically not implementing it in a reasonable way (i.e. it would flush the entire filesystem buffer and wait for completion instead of just the requested file's outstanding blocks). Not sure when/if that was fixed - but it is also probably behind the old impressions that mysql is faster than postgresql. -- Les Mikesell lesmikesell at gmail.com