3.5 Terabyte NAS Reviewed

Steve Kerrison writes "Thecus' new N5200 NAS can hold five SATA drives, which with currently available drives means up to 3.5TB (or 2.75TB in RAID-5) of storage before formatting. From the review: '£600. That's roughly what this will set you back, minus hard drives. Add in five 750GB drives and you'll be forking out a number closer to two thousand. However, act a bit more modestly and you can still have a terabyte (even in RAID-5) for under a grand.'"

Comments

Conversion for Americans

[cynicalmoose]

For those of you who don't know how much a pound is worth:

£600 = $1100
£2000 = $3700

(Yes, the pound is one of the heaviest currencies in the world - in that one GBP is worth more than one unit of other currencies)

Re:Conversion for Americans

[daBass]

one GBP is worth more than one unit of other currencies

There are some exceptions; probably amongst others, the currencies of Bahrain, Kuwait, Cyprus, Malta and Oman are all worth more in units than GBP.

Re:Build one instead?

[unts]

Hi there,

The reviewer, in person, here. Yes, you certianly could build a cheaper solution and whack Linux on it (the N5200 uses Linux too, incidentally). Of course, it depends on what features you long, how much you like fiddling, and what sort of case you fancy building it into.

Indeed, this thing isn't for everyone, but doesn't it look lovely?

Buffalo Terastation Pro

[Bushcat]

I have a couple of the Buffalo Terastation Pros (name depends on market). They seem to be a no-brainer at their pricing point if one doesn't get the largest-capacity model. Reason for two: one can do encrypted backups to the second, so my stuff is reasonably backed up and maybe secure. The things are almost silent in use, which is a way bigger factor then I ever thought it would be. Downside is the units don't support NFS out of the box, so they're just a tad too slow to stream video from. (Unless the problem is the Tvix5000U, a Korean product which is a great hardware design totally stuffed by abysmal software.)((As was it predecessor))(((And its portable equivalent)))((((Bugger, I spot a purchasing trend here I should have fixed))))

Re:Build one instead?

[Anonymous Coward]

sure, you could get 5 and have a NAS like everyone else does. Or you could get 24

Re:Build one instead?

[houghi]

If you want a movie, server, look here: http://www.kaleidescape.com/products/server.html
5.5 terabytes and you can even buy movies pre-loaded. Yes, you can add additional servers.

Re:Build one instead?

[Storklerk]

Yeah the N5200 does use linux. But I did not find any clear hint to this on the Thecus website.

Also I'm missing any documentation of how to upgrade the firmware to your own linux system.

If you want the source of their linux look here:
ftp://ftp.gpl-devices.org/pub/vendors/Thecus/

They tried to hide the linux, but without success:
http://gnumonks.org/~laforge/weblog/2006/02/24/

So until they openly say they are using linux and offer a way to upgrade the software on the system I will NOT buy one of these.

I did think about getting one of these. It has really nice features and if I could put my own linux system on one of the hard disk I could use it also as a dsl router and proxy (squid).

Anyone knows of a similar device with an upgradeble linux?

Re:Build one instead?

[Karzz1]

I built a 2Tb storage device w/another 250Gb for the OS a couple years ago as a backup solution for ~30 colo servers. I used a Tyan dual Xeon motherboard (there is a lot of compressing taking place on this machine), A 3Ware hardware RAID card, and a Chenbro 3u rackmount case with 12 SATA hot-swap bays and a single internal bay. I put 13 250Gb drives in it (2x250Gb software mirrored for OS, 10xRAID5 = 2Tb storage and 1 hot spare).

At the time the cost was ~$4000 while commercial solutions were closer to ~$8,000. I used CentOS 3 as the OS (4 was still in beta) and had to use the centosplus unsupported kernel in order to use reiser on the 2Tb array -- ext3 didn't work for some reason that I don't recall. The 3Ware card showed up with stock kernel modules as a SCSI controller.

I assume someone could build a similar system for about the same cost with much more disk space now. Also, if cost is a factor, the hardware RAID card (~$800) could be dropped in favor of software RAID and a single processor mobo could be used. I really** like the Chenbro case though and for the extra cost it leaves a lot of room for expansion if you were to start with only 5 drives and wanted to expand later.

Re:Build one instead?

[Anonymous Coward]

I've got a 2 TB server that cost around $2000 6 months ago (a significant fraction of the cost went to the motherboard needing to have PCI-E, which was only available on 64-bit motherboards at the time, which meant an expensive athlon 64 too, which was really horrible overkill).

I highly recommend the 3ware 9500S-8 controller, it is very well supported on linux (3/5 of the sections in the instruction manual were for installation on redhat, suse, and some other distribution), supports RAID-5, is SATA, supports up to 8 drives, and was very inexpensive considering it's features. It goes without saying that it's "real" RAID as opposed to software RAID. I've been running dapper server edition on it for six months, and couldn't be happier with it. 6 x 400 GIG generic hard disks, and when the time comes I can easily add in two more 400 GIGers to expand the array to 2.8 GIGs. I think it supports 500 GIG disks too, which means you can get up to a 3.5 GIG RAID-5 array.

Re:Build one instead?

[TCM]

Why is everyone always using 4 drives or 8 drives with RAID5? Considering most writes consist of 2^n bytes, you always need 2^n+1 drives in order to not waste any speed, i.e. 3, 5 or 9 drives.

I am using a software RAID5 and the difference between optimal and non-optimal is 71MB/s vs. 8MB/s writes! Hardware controllers could overcome some of this with their buffer memory, but I still think you should be using the optimal number of drives there.

Re:Build one instead?

[TCM]

I could only find this from the developer of NetBSD's software RAID implementation called RAIDframe http://mail-index.netbsd.org/current-users/2002/04 /19/0011.html:

The 'problem' with 4 disks is that you have (effectively) 3 data disks.
Since most times you're doing a 'power-of-two' write (e.g. 16K or 32K),
it's impossible to divide that power-of-two data by 3 and have a nice
full-stripe write. That leaves you with doing partial writes all the
time, and those are the ones that kill RAID 5 write performance.

In my case (NetBSD FFS) most writes are indeed 64K since I'm using a filesystem with a 64K block size. A whole stripe on my RAID is 64K as well (with 4 "data" components+1 parity component and 16K stripe size each), so a 64K write from the OS translates perfectly to 5*16K writes to the disk. This gives me over 107MB/s read speed and 71MB/s write speed from/to the raw device.

During testing I made a fatal error where, although the filesystem blocksize and stripe size matched, I had mistakenly offset the partition on the RAID by a number of blocks that was not a whole stripe. What then happened was that each 64K write didn't translate to 5*16K writes, but instead to 2* 4*16K reads (since each stripe is 64K and the 64K write from the OS overlapped 2 stripes partially), then parity recalculation of 128K data and then 2* 5*16K writes. This dropped the write speed to the mentioned 8MB/s.

I think the problem is equally bad if you try to write 2^n bytes of data to a prime number of data disks (3 or 5).

If you do it right, RAID5 write speed doesn't suck, not even with software RAID.

Re:Build one instead?

[zuzulo]

Another thing to remember when building high density storage appliances at the moment is that the MTBF for >=750 GB drives that use the new perpendicular recording tech (multiple layers of data - 2 at the moment - stored at each point) is actually higher than that for standard drives. That is, the new larger drives that use this tech are actually more reliable than smaller drives using the old tech. Seagate is the only drive manufacturer actually using perpendicular recording tech for retail drives, although this should be changing in the near future as more devices from other manufacturers make it into the retail chain.

I am not affiliated with Seagate or any other HDD manufacturer.

Re:A custom built alternative

[Saeger]

Just to see how reasonably low I could go, I spec'd out an even cheaper do-it-yourself Micro-ATX software raid5 box:

$34-44 - MicroATX MINI-tower case w/ 300-400W PSU, 4x int 3.5" bays + 1-2x ext 3.5" (or 5.25" bays w/ brackets)
$79 - MicroATX Asus Socket 939 MB w/ 4x SATA2, 2x PATA, pci-e, gigabit, integrated vid&audio
$92 - AMD Athlon64 3000+ (cheapest socket 939 cpu)
$22-$40 - 256MB DDR400 (or $40 for 512)
$25 - 1GB CompactFlash (80X)
$12 - IDE-CF Adapter
$14 - 1x SATA PCI-e controller (1 + 4 onboard = 5x sata and no PATA crap); micro-atx MBs with more than 4x sata aren't common. Would like 6x for a hotspare option.
$0 - FreeNAS, or roll your own.
= $278 - $306

Add 5X Seagate 320GB SATA2 drives @ $100 each, which comes to $773 total for a 1,280GB RAID5 NAS box. Not too shabby. Could get the drives even cheaper than $0.31/GB by waiting for a better with-rebate-hassle deal.

Biggest downsides to this kinda of thing:
1) setup time for h/w and s/w
2) no easy hotswap bays with blinken LEDs to tell you "THIS DRIVE IS DEAD/DYING; REPLACE ME!", so you have to rely on mdadm alert emails and SMART monitoring, then crack the case open and KNOW the sata order so you replace the RIGHT sdX drive.
3) ugly and bigger than it needs to be

When some company comes along and sells a 5-6 drive raid5 box like this for $150-$250 (instead of triple that) I bet it'll be a HUGE hit.