RAID 5 Setup for NAS

oli collett · 5 Feb 2011 at 15:24

Hi all,

I'm looking at upgrading my NAS/server to 8-10tb and i'm weighing up some options. At present i've got 5 x WD drives in RAID 5 running linux software RAID, but i'd like to move to a more reliable setup utilising a hardware RAID controller and of course increase the capacity.

Drive wise, I was originally thinking of using the WD RE4-GP drives, but i've heard that the Samsung F4 EG will be equally good for a fraction of the price? I'm more concerned about reliability than performance, but at £60 for the F4 EG I guess it wouldn't be the end of the world if one went wrong!

For a controller I was going to go with the LSI 9260, is this a bit OTT? The Server is mainly used for media streaming so I don't need ridiculous performance, but i'm concerned about the reliability/portability of software RAID

The Halk · 5 Feb 2011 at 16:18

Software RAID is a bad idea, as is using RAID5 with cheap drives. If one of the drives does fail on an 8-10TB array you then have to cross your fingers another drive doesn't crap out during the very long rebuild operation.

I have the proper alternative - and I do not recommend it. I have 8 x 1TB WD RE3 on an Adaptec 3805. It was very expensive to set up. And it's not the ideal solution.

What I would recommend instead is some form of disk pooling. Perhaps ZFS or one of the Linux NAS buids.

Windows Home Server Vail did have Drive Extender which was a great solution - it had a bit of parity checking, which would help against bit loss, and you could just double everything. So if you wanted for an example an 8TB array you'd just put in 9 2TB drives or so. Cheap as chips and as bulletproof as these things go. No RAID involved. Sadly Microsoft have removed Drive Extender, or at least have said it's being removed... they did hint that it might be replaced by a 3rd party solution.

In short though RAID is the wrong option for you.

img · 5 Feb 2011 at 17:07

HAve you looked at unraid?

Zarf · 5 Feb 2011 at 17:54

As mentioned, Rebuild times are prohibitive with large RAID5 arrays. Go for RAID10.

I'm in the process of making the switch over to a ZFS pool of mirrors (effectively RAID10). You have to add disks in pairs, but rebuild times are as low as possible, and it's easy to gradually expand capacity since the mirrors can be different sizes.
ZFS allows for lots of neat features too, like Deduplication and/or Compression on particular folders.

I've also looked at UnRAID, I like the concept but I'd prefer to have a single storage pool. With unRAID managing your space is a bit more irritating because folders can't be larger than the drive they are stored on.

oli collett · 5 Feb 2011 at 18:54

So, should RAID 5 be RAED 5?

ZFS sounds interesting but i'm currently running Ubuntu server, so I guess I'd have to switch over to an alternative, same would be the case with unRAID as well I suppose. Not sure how i'd transfer over my current array if i was going to do that though.

RAID 10 would be a more sensible option, I guess realistically I'd be looking at 6 x 2tb drives which would be plenty of space for my current needs

The Halk · 5 Feb 2011 at 19:20

I switched to Ubuntu last week! Pulled my hair out a few times but I now have it working.

You could look Greyhole?

You can get ZFS on Ubuntu.

Edit : Oh, both Windows and Linux can do software raid, which for storage I think is better than motherboard or pseudo hardware RAID.

SimonMaltby · 6 Feb 2011 at 12:25

My custom NAS box is built using an ION Motherboard / CPU and a Dell Perc 6i Raid Card (which I picked up for £120 new including cables for 8 SATA drives).

I have 8 640GB Laptop drives which sit in some nice quick release racks.
Originally I went for Raid 6 using all 8 drives but had some issues due to a twisted SATA cable meaning it was forever rebuilding. Now I have 2 Raid 5 Arrays one using 4 drives the other using 3 and then 1 drive allocated as a hot spare.

I would agree 100% that raid 5/6 means very long rebuild times, if it's a NAS that you leave on all the time, this may not be a problem. I have not tried Raid 10.

Hope this helps.

oli collett · 8 Feb 2011 at 18:48

After looking into some options, I think I'm going to go down the unRAID route.

It seems to be easy to manage and easy to expand which should suit my requirements nicely. I know it's not perfect, but it doesn't seem like any solution is really!