2009/12/11 Jeff Mahoney
btrfs is copy-on-write, which naturally introduces lots of fragmentation. As a way to combat this, it has an online repacker. Even if your system is able to boot immediately, that block map can become inaccurate at seemingly random times.
I'm curious - is there no way of selectively disabling that?
I'm not sure. I don't think you'd _want_ to.
Actually, that's not true. You wouldn't want it kicking in while running an i/o intensive workload.
One would hope the btrfs does "housekeeping" like that when general I/O is relatively idle. Like RAID background I/O sync ups. Hopefully the proposed "online defragger" for ext4 will have some way (madvise()?) of minimising disruption to priority tasks (rather than be the new locate(1) to destroy "interactivity").. Anyway expert lilo users can disable such features by using a different filesystem for /boot stuff and not using btrfs except where the features suit. Anyway looking at the pro/cons it looks like GRUB2 stands as the most realistic possibility to fulfill the requirements, worth doing some testing. If it gets picked up by more distro's, then there'll likely be increasing pressure to support it. Rob -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org For additional commands, e-mail: opensuse-factory+help@opensuse.org