----- Original Message ----- | Hi All, | We have a RedHat 6.2 cluster with 4 nodes using GFS2 for shared | filesystems. One of the filesystems we need to share is | /var/spool/mail. In general, with recent upgrades and improvements | to | GFS2, which has been working really, really well. We're starting to | see | some significant fragmentation on files in the filesystem, though, | even | after recreating the filesystem after the RHEL 6 upgrade. My | understanding was that there were fixes in RHEL 6 that made | defragmentation un-(or less?) necessary, but we're seeing a | disturbing | increase in the amount of fragmentation since the upgrade. By the | way, | we're seeing numbers in the range of 4,000-6,000 extents/GB for some | of | these files, which seems a bit large. | So, I've got two questions: | | 1. At what point should we be worried about the number of | extents? | 2. Are there plans for a defragmentation tool? | | | Thanks! | | -- scooter Hi Scooter, GFS2 has never really managed file fragmentation, so it's not a new problem. Simultaneous writes to GFS2 will cause fragmentation. There's nothing different in 6.2 regarding file fragmentation from any other release of the kernel, so perhaps you can give us more details about what you're seeing? Having said that, Red Hat's GFS2 team HAS been actively developing code in the GFS2 kernel code to reduce file fragmentation. Many of these patches have already been sent upstream (to the kernel.org kernel), and we have working prototypes for 6.4. Here's an upstream link to one of our major defrag patches (there are others related to it scheduled for the next merge window): http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=8e2e00473598dd5379d8408cb974dade000acafc We currently don't have any plans for defrag tool for GFS2. In theory, you can always copy the data from an old file system to a new one using this new kernel code, and it should be less fragmented. Regards, Bob Peterson Red Hat File Systems -- Linux-cluster mailing list Linux-cluster@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cluster
