Nov 18, 2008 4:34 PM | 4 Comments

So I recently found myself looking for an external RAID storage solution. My data needs had outgrown my PC, and I was getting tired of micromanaging all my stuff.

Time for a storage upgrade. I wanted RAID 5, and since there was no space left in my PC, I decided to go with an external server or network attached storage (NAS) solution.

RAID 5, for those not aware, is an array of disks with data redundancy built in. Say you have four 1TB hard disks. You can build an array (a single virtual disk, if you will) that has a capacity of 3TB. For the loss of 1TB of storage space, your array can support the failure of any one hard disk without data loss. And what are the chances of two disks failing at once, right?

Now, traditionally, hardware NAS products that support RAID 5 have been ridiculously expensive. Until fairly recently it was much more cost effective to buy a really cheap PC in a really big case and then load it up with as many hard disks as you could fit. But this time I wanted a neater solution that didn’t require me to install and manage an OS. So I went with a low-cost NAS box.

At first I was looking at one of Western Digital’s new ShareSpace devices, and I managed to borrow one from Western Digital for testing.

The ShareSpace, officially $750 with two 1TB hard disks or $1500 with four, is a good buy (although having just checked the price online, the actual selling price of the ShareSpace seems to be a little higher than the RRP).

It's been very stable for a while now, and while its RAID 5 performance isn’t stellar (I get about 10-15MBps over Gigabit Ethernet), it’s passable. It’s also easy to manage and easy to install new hard disks to.

The ShareSpace supports four hard disks, and if you buy the 2TB model you have two free slots for future expansion (and quite frankly, you’re much better off doing this, given the strange pricing of the device). For some crazy (and exceedingly annoying) reason, those hard disks have to be Western Digital disks – try to put any other disks in there and it recognises them, but says you can’t use them. It also doesn’t support UPnP AV/DLNA, which is used for streaming media to devices like the Xbox 360 and DLNA TVs.

If fact, I was so annoyed with these restrictions (especially the hard disk model issue, as I had already purchased two Seagate drives) that I decided to go out and get a Thecus N4100+ instead.

Purchased for around $550 sans hard disks (it has slots for four), the Thecus works out to be a little more expensive than the ShareSpace, but on paper it looked like a better product: support for DLNA, no hard disk model restrictions. That was on paper. It turned out to be a horrible mistake. The N4100+ is incredibly slow in RAID 5 mode – I routinely get only 4 or 5MBps, which is really, really bad. Apparently the processor in the Thecus 4100+ just isn’t powerful enough for the maths that RAID 5 requires.

Some online research revealed that the N5200, although a few hundred dollars more expensive, is a much better purchase and can deliver RAID 5 speeds many times that of the N4100+.

That was just the beginning of the bad with the Thecus. One of the hard drives failed. OK, not necessarily the fault of the Thecus so much as of Seagate (a million hours mean time between failure, my butt!), the drive manufacturer.

But RAID 5 is supposed to be able to tolerate a failed hard disk without data loss. Nuh-uh – the Thecus decided to delete the entire array, causing me to lose nearly two terabytes of data. Thankfully, with the help of Thecus’ fantastic tech support team I managed to get a large chunk of that data back, but quite frankly I won’t be trusting my data to the device again.

Of course, this extended anecdote is really an opportunity to ask you about your experiences with NAS and other external storage devices. If you’ve found one you trust and can recommend, I’d love to hear about it in comments.

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Les Harris Nov 18, 2008 5:08 PM	I am dead keen to see answers on this one! I want to set up a Raid NAS. Hard drive compatibility and transfer rate without breaking the bank are important. Les Harris
midbear Nov 18, 2008 6:35 PM	We have a western digital worldbook ll 1tb at work and I must say it is dead simple to use and set up and so far has work perfectly for the purpose we use it for - which is a backup device. For data transfer though it is slow, but its ease of use will outweigh this issue for a lot of people. For redundancy it uses raid 1 which is one of the reasons it is slow, but it is also the safest form of raid for backup purposes. I also recently played with nasLite, which is very inexpensive way of turning an old pc into a nas device and again was easy to set up and works well as storage device, but doesn't come with any built in backup software. But you could use a program like syncback to sync folders to it, and it is quick as well. The downside (besides having another grey box connected to the network) here is that naslite only uses hardware raid. If there is no raid it uses JBOD, and I am yet to find out good that is if I lose a hard drive.
erik00 Nov 19, 2008 1:26 PM	Hi there; I'm the Thecus Product Manager at Altech, Thecus' exclusive distributor in Australia. I'm very sorry and frankly; very suprised to hear about your poor experience with the N4100+. Normal tranfer rates on the N4100+ should be around 15-20MB/s, around twice as fast as the Western Digital ShareSpace. In fact Thecus is renowned as the performance king in NAS for the home and SMB. Their N5200B Pro transfers at over 70MB/s, which is much faster than any of their competitiors. Also, the RAID-5 issue of all disks being marked bad is a common one to all RAID-5 controllers (just ask Leo Laporte of twit.tv). We would recommend a dual-array strategy: RAID-1 : Critical Data JBOD : Non-critial data or for a 5-bay NAS: 2 disks - RAID-1 3 disks - RAID 5 Finally, great to hear about the excellent customer service you received from Thecus. Erik Kab. Thecus Product Manager - Altech Computers
Nathan Taylor Nov 19, 2008 5:16 PM	Yes, I've heard that the N5200 is a substanitally better product (as I mentioned in the post above), because it uses a real PC processor rather than the lower-power ARM processor in the 4100+. I should also note that the speeds quoted above are RAID 5 write speeds. RAID 5 is always a slower to write than read, because it has to write parity information as well. It's the calculating of the parity info that kills the N4100+. When reading from the device I get about 13-14MBps. I get about 18-19MBps reading from the Western Digital.