01.12.2017 21:04, Austin S. Hemmelgarn пишет: > On 2017-12-01 12:13, Andrei Borzenkov wrote: >> 01.12.2017 20:06, Hans van Kranenburg пишет: >>> >>> Additional tips (forgot to ask for your /proc/mounts before): >>> * Use the noatime mount option, so that only accessing files does not >>> lead to changes in metadata, >> >> Is not 'lazytime" default today? Sorry, it was relatime that is today's default, I mixed them up. > It gives you correct atime + no extra >> metadata update cause by update of atime only. > Unless things have changed since the last time this came up, BTRFS does > not support the 'lazytime' mount option (but it doesn't complain about > it either). > Actually since v2.27 "lazytime" is interpreted by mount command itself and converted into MS_LAZYTIME flag, so should be available for each FS. bor@10:~> sudo mkfs -t ext4 /dev/sdb1 mke2fs 1.43.7 (16-Oct-2017) ... bor@10:~> sudo mount -t ext4 -o lazytime /dev/sdb1 /mnt bor@10:~> tail /proc/self/mountinfo ... 224 66 8:17 / /mnt rw,relatime shared:152 - ext4 /dev/sdb1 rw,lazytime,data=ordered bor@10:~> sudo umount /dev/sdb1 bor@10:~> sudo mkfs -t btrfs -f /dev/sdb1 btrfs-progs v4.13.3 ... bor@10:~> sudo mount -t btrfs -o lazytime /dev/sdb1 /mnt bor@10:~> tail /proc/self/mountinfo ... 224 66 0:88 / /mnt rw,relatime shared:152 - btrfs /dev/sdb1 rw,lazytime,space_cache,subvolid=5,subvol=/ bor@10:~> > Also, lazytime is independent from noatime, and using both can have > benefits (lazytime will still have to write out the inode for every file > read on the system every 24 hours, but with noatime it only has to write > out the inode for files that have changed). > OK, that's true. -- 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
