I am a college student (compSci) that moves around a lot with a laptop. I back it up often, but I dont want a simple usb hd that can be stolen from my dorm and/or damaged (its already been damaged). I am making a file server with RAID 1 that will sit at my parents house for safer backups. I just need a few pointers, I have never experimented with RAID before.

Software: Fedora 14 - Software RAID 1. I will only have ssh running on a port other than 22, behind a router, with keyed entry only so I can remotely backup my stuff.

Hardware: A new(ish) P4 mobo with two (2TB) hd's (for RAID 1) and one small hd for the OS.

My questions:
1) Should I have the OS installed on a separate drive or on the two RAID drives? I am using software RAID, not hardware, so I assume I need two external drives for the RAID.

2) Should I be using more then two hd's for a RAID 1 array?

3) How can I encrypt the RAID drives? As I said before, I have no experience with RAID.

4) If the OS drive fails, can I just grab a new hd and install Fedora on it to get the data off my RAID array? Or do I need to image the Fedora drive every so often?

5) If one of the RAID drives fail, is there some sort of daemon that can tell me? I will not be at my house physically, so I will not be able to hear scratching platters :P. Also, because the size of a single disk in the array is 2 TB, can I just go out and get any kind of 2 TB drive to replace the failed one?

6) If the MoBo fails, can I just pop in a new one (of any kind) and continue using my same array?

Thanks for any help!

PS, If anyone has any suggestions/concerns about my ssh-to-backup-server, security or otherwise, please let me know.

I am not a huge fan of software based RAID, preferring a solid and proven hardware RAID controller with a battery backed cache system. However I have played with software RAID a little and for a low price solution it is better than a cheapo fake RAID controller.

1. It is really up to you. There are some reasons to NOT install the OS on the same drives you will be keeping your data, such as the limits of an MBR disk (2TB), and loss of storage space to the OS partitions. If your system can handle four drives I would say buy two smallish drives to install the OS on in a RAID 1 array, and two larger storage drives in RAID 1 for backups.

2. The number of drives will all really depend on capacity needed, budget, and what will physically fit into the system. If you are using consumer SATA drives and will likely be away from the system for long periods with nobody who can swap drives readily available having an online spare drive would be a good idea. This way if one drive does fail you can rebuild to another drive already in the system and then swap when you get home.

3. Do you want to encrypt the whole drive or just portions of the file system? Either way it should be no different than if you are using a single drive. Basically all the RAID layer is doing is adding an extra logical layer between the OS and the hardware. Just setup encryption on the RAID logical volume rather than a physical volume and you should be fine.

4. I think this will depend a bit on if you do the encryption you asked abut above. Encrypting the drive makes things more complicated. But if you are just talking an unencrypted drive then just adding to a system and copying over the configuration should be sufficient.

5. There are command line arguments you can run to check the status. Also in CentOS at least there is a weekly check scheduled as a cron job to check the status of the array, and combining that with something like logwatch should let you know. You could also custom script something to just run checks and email the results out to you however often you like.

6. I think so, but have never tried.