My main issue is using snapshots to backup a system implementing LVM2.
I'm using LVM2 on a testing server, using ReiserFS as the filesystems for the partitions. The system is running 2.6.15-1-k7 as the kernel. Please correct me if I'm wrong. I would use the snapshot functionality to create a snapshot of a live system, and then backup the system using the snapshot instead of the actual system. This is because the snapshot only contains the data that has changed from the point in time that the snapshot happened, and the rest is just references to the unchanged data on the live filesystem. A snapshot is NOT a permanent backup solution by itself. The LVM howto, section 3.8, states that any filesystem that is to have a snapshot taken of it should be in a consistent state. I do maintain databases that reside on the testing server, and I am not sure how to verify that the filesystem is in a consistent state. Also the howto mentions a vfs patch for the LVM1, and that many filesystems automatically support it in 2.6. Does this mean that since my machine is using LVM2 and the 2.6 kernel that the locking is automatically done? I have done some reading regarding snapshots in general, and it seemed that if the filesystem was not in a consistent state, everything BUT the database would be fine. One of the suggestions was to use the snapshot feature on everything except the DB, and use a dump feature in the database, for example MySQL. Is there any suggestions, techniques or guidance that could be offered? Thanks,
