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shifuimam · Nov 17, 2011, 04:13 PM

Soooo I don't know where this should technically go...mods, move if necessary.

Anyhow.

My server broke several months ago, due to an ill-advised attempt to expand the size of the software RAID on it. I finally recovered as much data as I could and now have to start over with the server so that I can put all my files back on it.

First of all: no, hardware raid is not an option. This is a very basic home server and software RAID has served me just fine (the only problem I've had with it was when I broke it doing something it didn't really support to begin with). I have no interest in shelling out hundreds or even thousands of dollars for a hardware RAID controller. Additionally, I'm uninterested in using an OS other than Server 2008 R2. My entire network is Windows 7-based aside from a couple ancient Macs, a MB, and my Android devices, and Server 2k8 has the best integration with Windows-based clients (obviously).

I have four 1TB hard drives. I have less than 1TB data total, although I'm sure that will change over time. The main goal is to make sure that my really important stuff - that is, things that are irreplaceable, like graphic design projects, documents, and photos - is sufficiently backed up. I also have a USB 3.0 2TB external drive I originally bought for the purpose of recovering my data after my catastrophic RAID failure. I now want to factor that in as a possible backup location.

I'm thinking about several options:

Straight up RAID 5, giving me a total of 3TB disk space. Use external drive with a backup program like Cobian Backup to keep diff backups of my critical data.
RAID 0+1 (Striped then mirrored), giving me a total of 2TB disk space. I wouldn't really *need* to factor the external drive in with this solution, as all my data would be redundant. I lose a terabyte of storage with this configuration.
RAID 1 and 2TB dynamic disk. 1TB redundant storage, plus 2TB non-redundant storage for the replaceable stuff (media, etc.). This would also give me 3TB storage and not require any third-party software running to keep backups of my files. I could even use the external drive as a shadow copy volume with the backup utility included in Server 2008 R2.
Some other configuration I haven't thought of yet.

I'm just curious to know what others would do in this kind of situation. I want to have a good amount of storage space, but having redundancy is also critical. I've already decided to start uploading all my photos to Flickr as an online backup (I have Flickr pro, so bandwidth isn't an issue), but otherwise I want to come up with something with the storage capacity I already have.

Thoughts?

Waragainstsleep · Nov 17, 2011, 08:48 PM

How long did it take you to accumulate 1TB of data? How long do you expect it to take for you to double that amount? How long do you plan to keep this system running?

If you think a 2TB RAID will last you a year or two and are happy to replace the array if not the whole system at the end of that time frame, then RAID 0+1 might be a good option. Use the external 2TB as a complete off site backup.

If you need it to last a little longer and you want 3TB+ then you have to go RAID 5 without much redundancy. You'd need to be more selective about what backs up to the external too since it won't hold everything anymore.

I wouldn't be so quick to write off hardware RAID either:

Newegg.com - HighPoint RocketRAID 2310 PCI Express x4 (x8 and x16 slot compatible) SATA II (3.0Gb/s) Controller Card

Newegg.com - HighPoint RocketRAID 2640X4 SGL PCI-Express x4 SATA / SAS (Serial Attached SCSI) Controller Card

P · Nov 18, 2011, 06:08 AM

Well, what I would do is get a 4-bay Drobo and stick the drives in that. That way you can grow the array as needed later on. Failing that, RAID5 is the best solution of the above, but it depends on the exact software setup you will use for it.

Waragainstsleep · Nov 18, 2011, 07:11 AM

I really don't trust Drobos.

mduell · Nov 18, 2011, 03:43 PM

RAID is useful for high availability; it's a lousy backup.

I'd say stripe a pair of disks for a 2TB working volume. Back up (not clone) the important files to another 1TB internal drive and a 1TB external drive which is kept off site most of the time.

besson3c · Nov 18, 2011, 04:50 PM

Did you guys miss this requirement?

First of all: no, hardware raid is not an option. This is a very basic home server and software RAID has served me just fine

Software RAID-wise, do you realize that non-ZFS RAID-5 is an unsafe option? Google the "RAID 5 write hole" to find out more, your safe options for RAID 5 are a RAID controller (which includes a little battery to do the last of the writes should the power be yanked away, which is what puts software RAID 5 at risk), or ZFS (which solves this problem with its copy on write stuff).

Unless there is a solution for Windows that includes a para-virtualization block device driver to give your VMs direct access to your disks, your options seem pretty much limited to software RAID 0/1. You are probably well aware of the dangers of RAID 0 too.

besson3c · Nov 18, 2011, 04:54 PM

Info on the write hole:

Standard RAID levels - Wikipedia, the free encyclopedia

besson3c · Nov 18, 2011, 04:55 PM

Info on the write hole:

Standard RAID levels - Wikipedia, the free encyclopedia

cgc · Nov 18, 2011, 06:17 PM

Originally Posted by besson3c

...Google the "RAID 5 write hole"

Where's the Beavis and Butthead emoticon when you need one..."uh...you said google your write hole...uh huh huh huh..."

besson3c · Nov 19, 2011, 04:34 AM

Hehhe... nice!

P · Nov 19, 2011, 06:52 AM

Originally Posted by besson3c

Software RAID-wise, do you realize that non-ZFS RAID-5 is an unsafe option? Google the "RAID 5 write hole" to find out more, your safe options for RAID 5 are a RAID controller (which includes a little battery to do the last of the writes should the power be yanked away, which is what puts software RAID 5 at risk), or ZFS (which solves this problem with its copy on write stuff).

Or a UPS. Which I assumed was there to begin with since it was a software RAID, but maybe I should have pointed it out.

OreoCookie · Nov 19, 2011, 07:15 AM

You have included a lot of boundary conditions here. But let me address one point before making any suggestions: you seem to think that a RAID is a replacement for a backup. It is not. A RAID will only give you some protection against hard disk failure, but nothing more. As you've experienced for yourself, if you toy with the server (or lightning strikes or whatever), you will lose data.

Your current storage requirements are rather small and IMO a RAID is not necessary. All of your data fits on one drive and thus, you have little advantage to create a RAID. On the contrary, a RAID will make it harder for you to expand storage, create additional complexity which may result in data loss (e. g. by messing up the software configuration).

If you want a more flexible storage solution, I'd point you towards FreeNAS, a FreeBSD-based NAS which uses ZFS for storage. ZFS is very flexible when it comes to storage and extremely fast. It obviously comes with SMB and iSCSI support.