We are looking at getting a new server, and we are thinking about getting 4 drives in a Raid 1+0 array (mirrored and striped).
However, we cannot get more than 4 drives, so we can't get a 5th drive as an "onsite" backup. (We of course will also have an offsite backup, but we need an "onsite" backup to create the files to later move offsite, and for easy access to restore accounts or files from a previous time.)
Would it be a problem if we created our /backup partition on the same 4-drive Raid 1+0 array as the rest of the system? Backups would be weekly, but I'm not sure if backing up from a RAID 1+0 array to itself would cause high load or iowait. We would be using cpbackup for the backup.
Also, if we have to hard reboot the server, could that cause array corruption? I've read conflicting posts about that. I know a hard reboot can generally cause problems with or without RAID, but does it cause more problems with RAID (or increase the chances of problems)? Might I be stuck one day waiting for the entire array to rebuild?