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I am in the process of shopping for drives for my Linux Server (CentOS 6.3). I think I have it narrowed down to RAID 5 or RAID 10 (have to see what hard drive prices do) and using the Linux Software RAID. I like the software RAID because I can configure it to email me about drive failures, etc. I am just wondering one thing... say my system gets corrupted, what are the steps necessary to mount that RAID volume on a different Linux installation? If this happened I would be willing to install a new system that is compatible, it doesn't have to be "universally compatible" with other distros or anything... Is there a configuration file I can save and then rebuild the array from that? Or does it happen automatically?

I will be using the RAID as a backup system, so redundancy is important, but it isn't the only place the data will be stored, I will probably also buy one other drive that will hold the entire size of the array (for instance if I get 3x 1TB drives for a raid 5, my other drive will be a 2TB) to use for off-site or at least offline backup. I'm a little paranoid about data now since I lost many pictures a few years ago.

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up vote 1 down vote accepted

How often are you going to make the backup? If not often or if you make incremental backups then skip the fourth drive. RAID5 might not be the best for many small writes, but RAID 10 in addition to another disk is pure overkill.

(Written by a person with his data on a 4 disk RAID 5 and backups on two separate 2TB drives.)

Keeping a copy off-site is more likely to increase your security (e.g. in case of theft or fire).

As for the actual question: Any install with the md driver should work. It does not need to be CentOS. This is one the th4e nice advantages of Linux software RAID over IRRT.

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Which backup are you talking about the frequency of? The backups from my computers (at least 5 computers, a mix of windows, linux, and mac) or the backup of the server to an external drive (off-site)? I will do one initial Image of each computer for restore purposes(probably no data on the image) then incremental backups nightly with perhaps a full backup every week/month that gets archived until the next one runs. I am definitely leaning towards an off-site backup, so in that case would you suggest RAID 5 or something else(RAID 1?) – Kyle Jul 26 '12 at 16:15
I was thinking of the speed of the backup from a directly attached computer. Obviously this is not the case. In which case you only have to keep the write speed of the RAID array equal or higher than the wire speed. (Assuming no simultanious backups via ethernet and no huge delays when the backup checks the differences between archived files and existing backups.) – Hennes Jul 26 '12 at 16:37
It is directly connected to gigabit. Right now I just have a single 500gb drive in there and it maxes out the gigabit connection to 1 computer (~120mbps) Are you saying if I have faster drives I could get TWO concurrent ~120mbps streams from seperate PC's? Two or three of the PC's will be gigabit wired and the rest wireless. – Kyle Jul 26 '12 at 17:01
No. I think that the RAID might be able to handle data faster then the network. Which is why I think (performance wise) a faster RAID 10 does not make sense compared to a RAID5. I expect both to be limited by network speed. – Hennes Jul 26 '12 at 17:06
Ok, thanks! Probably going to go with a RAID5 unless I find some reason not to. I'm glad someone besides me thinks a RAID10 is overkill ;) – Kyle Jul 26 '12 at 17:08

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