04-22-2009 08:07 AM
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04-22-2009 09:05 AM
04-22-2009 08:50 AM
04-22-2009 09:04 AM
04-22-2009 09:05 AM
04-22-2009 11:45 AM
Here is why I would always recommend number 3 (with a few exceptions of course)
1. A FullVM snapshot by itself WITHOUT being mapped is only useful if you
a) need just the image for entire restores (not any individual file recovery within that full backup)
b) You need to save on time doing the entire image and cannot afford the overhead required for mapping.
2. You don't want to use a File only version because again, you will not get any system files or vmware files (depending if you're the type who is okay with rebuilding a core server image first and then dumping add ons) but it will not contain any registry info as well.
3. Just doing the FullVM mapped by itself regularly is useless - it just takes up space. With doing number 3, you are saying that it'll do the fullvm mapped first and then incrementals will be handled similar to the WindowsNT backup except that it DOES copy all the files that have been incremented first to the vcb.
4. If you use a FULLVM snapshot and want to restore a file, it doesn't take the same size as the entire snapshot compared to regular flashbackup.
You should understand that having the files and images copied over via san for performing the backups is VERY good when it comes to reducing the load taken by the backed up servers. If you run flashbackup or windows-nt backups directly on a system, you have to use that particular system's resources for this, versus a quick snapshot offload of the image that reduces performance impact.
Sometimes you'll actually have to choose a FullVM without being mapped or the file level only:
1. If the system that you are attempting to backup is EXTREMELY busy with using I/O load, there is the chance that a snapshot cannot occur (the system needs to be idled long enough for it to put a lock on the writes). Also, if theres not enough storage space on the VM for writing the extent of writes that occured during the snapshot, you can crash your VM.
I could think of more but my head would start to hurt.
Let me know if you need any more information, we mostly run VCB proxy backups here. Just remember, even thoguh the initial performance of a backup with just flashbackup only may be fast, if its not mapped and you have a disaster in which you need to restore some files, you have to restore the entire flashbackup image which takes more time versus when its mapped which would take only as long as it takes for those few files. All DR plans should be looked at in the sense of restore times, not necessarily backup times.
04-22-2009 01:47 PM
04-23-2009 03:50 AM
thanks for the replies, I think that's cleared everything up, it boils down to whether you NEED to perform image restores or just file level restores. Of course, with flashbackup and levels 2 & 3 you can do image and file level restores, it just takes more time to back up and will use a little more space (if lots of deletions on the vm has occured).
thanks for the info about 3Fullvm backup, I thought the full and incr backup image was copied to the proxy server, didn't know the incr backup just created a mount point/link, useful to know.