On Wed, Feb 10, 2010 at 7:55 PM, Josef Bacik <josef@xxxxxxxxxx> wrote: > On Wed, Feb 10, 2010 at 06:15:26PM +0000, Mat wrote: >> Hi guys, >> >> First off: you guys are doing amazing work ! >> >> btrfs "Better-FS" gets more and more stable, fast and space-efficient than >> all/most of the other filesystems :) >> >> >> It being able to survive compiling of openoffice, chromium webbrowser and other >> stressful stuff is a testament to its ever growing maturity >> >> >> Now on to my question: >> >> Since I'm using btrfs on more and more test-partitions on my system and also am >> into energy saving: >> >> is the following mount-option which exists for reiserfs, ext2-4 and reiser4 >> (tmgr.atom_max_age) also planned to be implemented for btrfs ? >> >> commit=nrsec >> Sync all data and metadata every nrsec seconds. The default >> value is 5 seconds. Zero means default. >> >> (in this case ext3) >> >> if yes, when will it be added ? >> >> > > It would be simple enough to do, but keep in mind that btrfs doesnt act like > ext2/3 does, so the commit doesn't necessarily mean _all_ data will go down to > disk, just data thats been allocated and writeout has been started on, which is > mostly controlled by the vm's dirty writeback stuff or if the apps you use have > been using fsync(). Any metadata thats been dirtied will be sync'ed every 30 > seconds. Doing much more than that is just widening the window for you to lose > new files and stuff (again, if they've not been fsync()'ed). Personally 30 > seconds is a good balance between being safe and saving battery life, but I'm > sure at some point we'll expose the commit interval via a mount option. Thanks, > > Josef > Thanks for your answer Josef ! I'll tweak /proc/sys/vm/dirty_writeback_centisecs, the other /proc/sys/vm/dirty* knobs for now and stick to the limit of 30 seconds Regards Mat -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
