Hi All, On 28/08/2012 11:24 AM, Christopher M. Bailey wrote:
I'm currently getting our DR system fine tuned at work, and as part of this I would like some software to take images of some of our larger Linux servers (RHCE 5 & 6) similar to how programs like Shadow Protect does for Windoze based systems, in other words while the system is live. Some of these server have up to 6TB of data stored on them and as you could appreciate, downing the server to run something like Clonezilla would take far too long to be practical. I would also like to be able to schedule these snapshots, say once a week.
Unless I am mistaken, all Shadow Protect does is create snapshot of the filesystem at a point in time. No different to taking an LVM snapshot. If at that point in time there are processes still with open files and data in memory, then you have every risk of corruption and lack of a suitable backup. Non-database files are less likely to be a problem with rsync type backups -- I use rsnapshot for these. But database tables need to be fully consistent and so a short "freeze" will be required to be sure that everything is good. Lots to consider, are you using Xen, KVM or any other virtualization in your setup? Are you using RAID1 and can you shutdown briefly, disconnect a drive from RAID1 (preferably with 3 or more RAID members in normal operation). LVM snapshots are also a good option. I shutdown entire VM's just long enough to snapshot all file systems, then restart the VM and proceed with backing up off the snapshots. How many and what type of disks make up the 6TB ? How are they set up? Using dump tools is likely to cause problems unless the dump is of a consistent snapshot. Linus sees dump of running file systems as "stupid" because you can never be sure that the OS has written everything to disk, so you cannot guarantee the state -- unless of course it is an unmounted snapshot area that you are dumping, you will not get a "proper" backup. Oracle has been claiming production ready BTRFS, but I don't know anyone whom really believes that, I mean *really* believes. Using BTRFS today has it's own risks. With 6TB of data, you really should have RAID1 protection at least and LVM snspshots with perhaps the rsnapshot tool and/or dumps (again of non-running file systems). I would say that you need a standby server to rsync to as well, a DR server, best at a separate DR site if possible. Cheers -- Kind Regards AndrewM Andrew McGlashan Broadband Solutions now including VoIP Current Land Line No: 03 9012 2102 Mobile: 04 2574 1827 Fax: 03 9012 2178 National No: 1300 85 3804 Affinity Vision Australia Pty Ltd http://affinityvision.com.au http://securemywireless.com.au http://adsl2choice.net.au In Case of Emergency -- http://affinityvision.com.au/ice.html