Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I would like to set up a server at home that will have several roles, but the primary and most critical role would be a file server. It will host family photos and videos among other things that I do not want to lose under any circumstances. I've read about RAID and understand it's purpose, but I have never set up RAID before. The main reason I am interested in a RAID setup is for protecting and recovering the data, not necessarily speed (but that's a nice plus).

The system I would like to buy is a small microserver that has 4 hard drive slots. It comes with a 250GB drive installed. My thought was to use that drive to host the OS and a few programs, and buy 3 1TB drives to put in the other 3 slots. RAID 5 makes the most sense for what I am thinking. Unless I'm mistaken, that would let me store up to 2 TB of data and allow me to recover it if one hard drive dies. To avoid having to buy more hardware, I was planning on setting up software RAID.

Here is my question: what if the OS drive dies? Once I replace it, can I configure the fresh install of the OS to use the RAID drives or does my data become inaccessible?

share|improve this question

closed as off topic by Ward, cjc, Zoredache, MadHatter, MDMarra Mar 14 '12 at 14:09

Questions on Server Fault are expected to relate to server, networking, or related infrastructure administration within the scope defined by the community. Consider editing the question or leaving comments for improvement if you believe the question can be reworded to fit within the scope. Read more about reopening questions here.If this question can be reworded to fit the rules in the help center, please edit the question.

RAID != backup. – joeqwerty Mar 9 '12 at 2:12
The Microserver is a very cute little box. I installed one last fall and found it to be very solid in its build quality. – Evan Anderson Mar 9 '12 at 3:44
for your purpose you should use dropbox or sugar sync to backup to the cloud – t q Mar 9 '12 at 6:36
@tq, sometimes, the sheer amount of data people has makes online backups unviable - but, for your most treasured photos and documents it's not a bad idea. – tombull89 Mar 9 '12 at 9:49
up vote 1 down vote accepted

This is what I am planning on doing shortly - using a MicroServer with 3 x 2TB disks in a Server 2008 RAID 5 with the 250GB disk as a boot volume (as I don't beleive S2008 can boot from a software RAID setup). The good thing about Server 2008 Software RAID is if the boot disk does fail it should be fairly simple to re-install on a new disk (or restore from backup) and then re-add the RAID array.

The Microserver RAID card only supports Hardware 0 and 1 - so, you could have two mirroed disks which the OS could be installed onto. Also, the Microserver has a USB port on the motherboard so you could even install FreeNAS to a USB stick and use that as a NAS - but not being a massive user of FreeNAS I don't know how well the recovery works.

As the others have said, RAID does not guard against accidental deletion.

If you really wanted peace of mind, you could buy two servers, and set them up in different parts of your house and get the "primary" server to copy to the "secondary" one every evening, or every weekend. The more places your data is, the more secure it is. I have my photos on my laptop, on a external USB HDD and on my data server - and also on a DVD. If my house burns down I'll be stuck (so would be best storing some online or at a workplace) but if that did happens my data would be the last of my worries.

share|improve this answer
with 2tb drives, you may want to reconsider raid-5, and go raid-6 or raid-10. The chances of read failure during rebuild is high otherwise. – Sirex Mar 9 '12 at 9:55
@Sirex, Server 2008 only supports software RAID 0, 1 or 5, not 10. I'd rather chance my data with RAID 5 (as it's backed up elsewhere) than running an unfamilliar OS that does have RAID 6/10 support. – tombull89 Mar 9 '12 at 9:58
Can you not make 2 raid 0 devices, and use raid 1 on those raid array devices (which is the same thing). – Sirex Mar 9 '12 at 15:32

You are laboring under a serious misconception. RAID is not a form of backup.

If you accidentally delete a file, or a software bug commands the system to overwrite files, the RAID system will cheerfully propagate the data loss to all drives. If something goes wrong in the RAID controller or the RAID headers get corrupt, you may be unable to get the RAID array operating.

RAID just lets you get back up faster, and avoid data loss, in the event of a drive failure.

share|improve this answer
+1000 if I could. RAID is for fault tolerance, not backup. Backup and fault tolerance are two completely different things. Backup is all about making extra copies of your data and storing them separately from the copy you use. Two totally different things. – Evan Anderson Mar 9 '12 at 3:45
Good comments, but I never used the word backup in my question. Your last sentence hits what I am getting at - I want to protect against drive failure. At some point I will setup an off-site backup as well, but that's out of the scope of my question. Under what circumstances would the RAID headers or controller get corrupted? – jdickson Mar 9 '12 at 15:30
@jdickson: If you are worried about losing your data, you need to back it up. RAID is about minimizing and avoiding down time, not protecting against data loss. – David Schwartz Mar 9 '12 at 20:42

You've made no mention of which OS you might use.

Most operating systems will have no problem mounting an existing software raid set. It shouldn't be hard to verify if this works for your installation if you've got bootable media.

Linux will happily boot off a single member of a RAID1 set implemented using lvm/dm - If it were me, I'd split the 3 drives - use the majority as RAID 3 or 5, but keep, say 80Gb slices for the OS and set these up as RAID 1.

share|improve this answer

If you OS disk crashes nothing happens to the RAID array it will still be intact. All you have to do is reinstall OS on a new disk install the RAID controller driver if you are using a HW RAID and all you data will be there in it.

share|improve this answer

Not the answer you're looking for? Browse other questions tagged or ask your own question.