On Mon, Jun 30, 2008 at 09:20:05PM +0900, Takashi Sato wrote: > Currently, ext3 in mainline Linux doesn't have the freeze feature which > suspends write requests. So, we cannot take a backup which keeps > the filesystem's consistency with the storage device's features > (snapshot and replication) while it is mounted. > In many case, a commercial filesystem (e.g. VxFS) has > the freeze feature and it would be used to get the consistent backup. > If Linux's standard filesytem ext3 has the freeze feature, we can do it > without a commercial filesystem. Is the following a fair summary? 1. Some filesystems have a freeze/thaw feature. XFS exports this to userspace directly through a couple of ioctls, but other filesystems don't. For filesystems on device-mapper block devices it is exported to userspace through the DM_DEV_SUSPEND ioctl which LVM uses. 2. There is a desire to access this feature from userspace on non-XFS filesystems without having to use device-mapper/LVM. Alasdair -- agk@xxxxxxxxxx -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
