Hi,
I'm going to start my dissertation work which is "Adding snapshop
capability to Linux kernel with copy-on-write support". My idea is add
it as another VFS - I know that there is some snapshot support in LVM
but it's working on "device-level" and I'd like/have to do it on fs level.
My idea is to use it this way:
- I have running system with some "/foo" dir
- I want to make snapshot of "/foo/bar" to "/foo/snap1"
- I run "mount -t snapshot /foo/bar /foo/snap1"
- This creates virtual image of "/foo/bar" to the "/foo/snap1" with
hidden file (something like journal) in "/foo/snap1" - all files are
linked to "/foo/bar"
- Whenever is some file/dir changed in "/foo/bar" there is created
physical copy of it to the snapshot(s) before writing changes (for
making records about this will be used the hidden file)
- Of course that one directory can be snapshoted more times
- Probably the hidden file with records about all snapshots and details
should be stored in "/foo/bar"
- Question is how to handle ACLs and EA for XFS/JFS/... and if it won't
collide with journal
I'd like to do it not only because I have to but I want people to use it
(I want to make it GPL) and maybe it will be one nice day part of Linux
kernel ;-)
So I'd like if you can send me any suggestions/tips/warnings/links etc.
before I start coding so I know what should I avoid/use.
Thanks,
Libor
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This archive was generated by hypermail 2b29 : Tue Apr 23 2002 - 22:00:30 EST