1 |
On Tue, 22 Dec 2009 16:51:08 +0200, Alan McKinnon |
2 |
<alan.mckinnon@×××××.com> |
3 |
wrote: |
4 |
> On Tuesday 22 December 2009 16:21:08 Christian Könitzer wrote: |
5 |
>> a question to b): |
6 |
>> Can you tell me a fs that supports snappshots (I'm planing to set up a |
7 |
>> new server so you can choose a new fs... (now I am using reiserfs)) and |
8 |
>> maybe how to use it (link)? So if you say "or LSM" does this mean I can |
9 |
>> achieve this also woth LVM? How? |
10 |
>> thx... |
11 |
> |
12 |
> None of the traditional filesystems (ext2|3, reiser) support snapshots. |
13 |
> ZFS< |
14 |
> Btrfs do, possibly ext4 also (the last is a hunch only). |
15 |
|
16 |
That's basically true. However btrfs is quite experimental still, and I |
17 |
have no serious experience with ZFS, it kind of turns me back the fact that |
18 |
it's a FUSE based fs, though it's certainly possible to use it even for a |
19 |
root system provided that your kernel can load the module at bootup |
20 |
(initrd), I have no idea if there's any downside. I don't have either any |
21 |
notice about snapshotting in ext4 (I remember the plan being discussed but |
22 |
I don't think it has been finally implemented, I'd like to be wrong on this |
23 |
one though). |
24 |
|
25 |
> LVM snapshots a volume, not the filesystem on it. So it tracks extents |
26 |
> that |
27 |
> have changed, not individual files. For backup purposes though, volume |
28 |
and |
29 |
> fs |
30 |
> snapshots are equivalent. |
31 |
> |
32 |
> Snapshots with LVM are easy as pie: |
33 |
> |
34 |
> - create a new volume which is a snapshot of an existing one |
35 |
> - mount the snapshot somewhere |
36 |
> - copy,backup,etc as you like. The volume is read-only so you can't |
37 |
break |
38 |
> it |
39 |
> - umount snapshot |
40 |
> - destroy snapshot |
41 |
> |
42 |
> The LVM man pages contain a wealth of data, as does Google and the LVM |
43 |
> documentation at redhat.com |
44 |
|
45 |
Yep, just googling for something along the lines of "lvm snapshot backup" |
46 |
should give you enough info to start researching. However, for this to be a |
47 |
possibility you first need to convert your system to use lvm. |
48 |
|
49 |
-- |
50 |
Jesús Guerrero |