Messages in this thread | | | From | "Takashi Sato" <> | Subject | Re: [dm-devel] [PATCH 0/3] freeze feature ver 1.8 | Date | Tue, 1 Jul 2008 18:12:32 +0900 |
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Hi,
Alasdair G Kergon 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?
Yes, you are right. We'd like to use the freeze feature without device-mapper/LVM.
> 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
Cheers, Takashi
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