Comparison of Nine SATA RAID 5 Adapters

Robbedoeske writes "Tweakers.net has put online a comparison of nine Serial ATA RAID 5 adapters. Can the establishment counter the attack of the newcomers? Which of the contestants delivers the best performance, offers the best value for money and has the best featureset?"

Comments

Eight or Nine?

[SirTwitchALot]

TFA says nine adapters, but the graphic says eight, whoops.

Re:Eight or Nine?

[pbranes]

They must have started counting at 0. Stupid off-by-1 errors. ;-)

Seriously, though, I have been seeing many servers start to come in with SATA drives. Right now it is low end and off-brand servers. Dell even ships SATA drives in their cheapest server line. Sure SCSI has high spin rates & throughput, but they are freakin expensive. A good SCSI raid controller costs close to $1000 and a good SCSI hard drive can cost $400. It is so expensive, that it is reallly worth it sometimes to get the SATA drives in servers. I haven't seen that reliability of SATA over SCSI is a problem. I'm truly hoping that SCSI goes the way of the dodo. Its a pain to use. Who know what kind of cable you're supposed to use with that external SCSI device. SCSI, in its current form, is just opening itself up to becoming antiquated.

Re:Eight or Nine?

[ackthpt]

TFA says nine adapters, but the graphic says eight, whoops.

It was a parity bit, ignore it.

Re:Eight or Nine?

[Phantom69]

From Page 2 of TFA:

Note: Since the original Dutch article was published in late January, we have finished tests of the 16-port Areca ARC-1160 using 128MB, 512MB and 1GB cache configurations and RAID 5 arrays of up to 12 drives. The ARC-1160 was using the latest 1.35 beta firmware. Furthermore, a non-disclosure agreement on the LSI MegaRAID SCSI 320-2E PCI Express x8 SCSI RAID adapter was lifted. The performance graphs have been updated to include the Areca ARC-1160 and LSI MegaRAID SCSI 320-2E results. Discussions of the results have not been updated, however. The results should be self-explanatory.

Re:Eight or Nine?

[FemmeT]

There are really nine adapters: 3ware Escalade 8506-8, 3ware Escalade 9500S-8, Areca ARC-1120, Areca ARC-1160, HighPoint RocketRAID 1820A, LSI MegaRAID SATA 150-4, LSI MegaRAID SATA 150-6, Promise FastTrak S150 SX4 and RAIDCore BC4852.

The results of the LSI MegaRAID SATA 150-4 and MegaRAID SATA 150-6 have been combined in the graphs since there is basicly no performance difference between to two in configurations up to four drives.

Re:Eight or Nine?

[hey!]

No, I think we're suppose to reconstruct the ninth view from the other eight.

32 pages? No thanks.

[Mr. Sketch]

After 32 pages, it's probably just best to skip to the conclusion:
http://www.tweakers.net/reviews/557/32

Where it has the executive summary:

Areca ARC-1120: highly recommended
RAIDCore BC4852: recommended
HighPoint RocketRAID 1820A: recommended

For several reasons, we will refuse recommendations on the remaing adapters in this comparison

I think that pretty much covers the jist of the article.

Interesting that the 3ware offerings performed...

[tabkey12]

quite badly! They've been synonymous with quality in the RAID industry for many years. Look at this:

3ware Escalade 8506-8 is lagging far behind the competition. Moreover, it misses important features such as online capacity expansion, online RAID level migration and RAID 50 support.

http://www.tweakers.net/reviews/557/6

What they say in the article is almost damning really...

Re:32 pages? No thanks.

[tabkey12]

But RAID is nota one size fits all game - the detail of the article is extremely useful for people who will be tailoring their RAID to a specific application. Yes, this article is specialised, but I hardly see how reducing it to a list of three, relatively meaningless names is helping.

Re:3ware me

[tabkey12]

Because of this perhaps. Occasionally it helps to read an article before making comments that just make you look uninformed.

Re:3ware me

[B3ryllium]

The previous poster had this to say:

3ware Escalade 8506-8 is lagging far behind the competition. Moreover, it misses important features such as online capacity expansion, online RAID level migration and RAID 50 support.

Don't plan on mixing Highpoint cards

[GoodNicsTken]

I had a Rocket Raid 100 (IDE 4 drive RAID1/0) and a RocketRaid 1640 (4 Channel SATA RAID 0,1,5) card. With nothing connected to the 1640 and 2 mirrored drives on the RR 100 the disks attached to the RR100 in bios show up on the 1640, and when windows gets to the boot screen it locks up.

When I removed the drives in windows, it booted up without problems. Highpoint has sent me diag tools to run rather than building this in their lab!

I'm not too impressed with them so far.

You know the cheap-reliable-fast triangle.

[lanc]

Well, cheap+reliable == linux + softraid + Enhanced Network Block Device + Enterprise Volume Management System (or LVM2). It is often faster than non-hw-raid (fake-hw controllers.

Re:Interesting that the 3ware offerings performed.

[atarione]

3ware needs to develop new chips for their SATA raid controllers they are using ATA bridges on these SATA controllers and of course the controller chips are several years old now.

3ware needs to step it up w/ SATA controllers.

Drivers?

[sjbe]

While I've admittedly not read the entire article (it's really long) I couldn't find much info about drivers. It seems the author basically assumed one would be running windows, which for servers (the most likely place for a RAID array) is a pretty poor assumption. I've tried a number of SATA RAID cards on my linux server (SuSE 9.1) and keep getting driven back to SCSI due to crappy/non-existant driver issues. Thank god for Addonics SATA-SCSI adaptors which work great and have saved me a bunch of money.

It's a nice article comparing performance but without a serious analysis of drivers along with it for Windows AND linux (and Mac if applicable) the article isn't complete. I don't really care which one is fastest if I can't run it on my system.

Re:Drivers?

[LWATCDR]

3-ware has very good support for linux

Re:Drivers?

[ajrs]

read the rest of the article. The fine article says which ones have drivers for different versions of MS, prebuilt drivers for linux, Bsd (which must not be dead), Mac, and if the source code is available.

Re:Interesting that the 3ware offerings performed.

[PDXNerd]

RAID 0 is not the most reliable thing in the world. Couple that with the unreliability of SATA (yes, I work in a Validation Lab and we go through dozens of these a day) you would *NEVER NEVER* want SATA in RAID 0 storing anything valuable. Swap, sure, but never data! That said, we test dozens of SATA raid controllers as well. The best performer in my experience has been the 3Ware 9500-8. Does it have many advanced features? How many people who will be using SATA raid really NEED those advanced features?

Re:Interesting that the 3ware offerings performed.

[arivanov]

Well... as someone who has both of reviewed 3ware adapters in production I am not amazed. They are nice, but nothing to shout about. They also have LOADS of PROBLEMS not mentioned in the article.

• 8506 SATA series prior to a certain board revision are extremely susceptible to bus noise. As a result you have to find a way to bastardize the PCI bus down to 33MHz and provide additional grounding. Even so, they are likely to cause random system deaths and serious memory corruption in most Opteron MSI and Assus motherboards as well as some other designs. Using in 1U and 2U chassis with riser cards is a no-no for the same reason (exemption for some buffered risers). As a side note, most resellers will try to stuff you with an old board despite the fact that they know about this problem.
• 9506 board and linux driver at least as of 2.6.9 defaults to no read cache, only write cache which is outright daft. It is also the major reason for low performance at least under Linux.

Both are nice cards, but I would not recommend them to anyone who does not have extensive PC hardware knowledge. They are fussy, carpicious and very hard to troubleshoot when they go wrong.

If it doesn't say

[cmefford]

3ware, It's a waste of /my/ time. So I really don't care what the tweakers think. The 3ware cards are reliable, easy to deal with, have brilliant drivers, good software, and they WORK! Always! I have a 5 of them. I have a friend who has 40, he agrees. I use a 2 channel as a backup-to-sata drive, (cheaper than tape), another 2 channel in a IIS server for payroll stuff, 1 4 channel for a mail server and 2 8 channels for file/web. I love'em. Nuff said.

My thoughts

[tonsofpcs]

Areca ARC-1120 looks better on each and every page except for the sequential read/write tests where it tends to come in third [I'm just reading off the graphs].
The RAIDCore BC4852 seems fastest for sequential reads/writes.

BOTH of these have linux support. The Areca supports: Mandrake (9.0),Red Hat (7.3, 8.0, 9.0, AS 3.0), Fedora Core (2, 2 AMD64), SuSE (7.3, 9.1 Pro, 9.0 SLES, 9.0 SLES AMD64)
The RAIDCore: Red Hat (9.0, AS 3.0), Fedora Core (1)
The Areca also supports Windows XP and Server 2003 64-bit versions and BSDs: 4.2R, 4.4R, 5.2.1 (incl. source).

Also, the Areca ARC-1160 (they finished testing after the original article was written, so it didn't make it into most of the text) appears at the top of all of the Index/performance tests, except for "Fileserver - Large Filesize - RAID 1/10" and "My SQL - Data Drive - RAID 1/10".

Re:Related Question

[beavis88]

From what I've heard, you should assume that you won't be able to swap cards out. You might be able to if you stick with the same manufacturer and they're using the same chipsets, but again, don't count on it.

SCSI vs SATA

[sjbe]

SCSI, in its current form, is just opening itself up to becoming antiquated.

Perhaps, though personally I've had far more trouble getting SATA (and IDE) drives to work than SCSI drives and I've used both extensively. Driver issues mostly. SCSI's performance is better in multi-user systems, it's easy to set up, drivers tend to be less problematic especially on systems other than Windows, and it can have more devices attached. People claim it's more reliable though I have no evidence of this, and frankly am a bit dubious of the claim. SATA is also easy to set up and is a lot cheaper, though the drivers are still less ubiquitous than with SCSI and performance doesn't match SCSI yet for multi-user systems. (on a single user system it doesn't matter much)

That said, the next generation of SCSI is Serial Attached SCSI which is compatible with SATA. A SAS controller will be able to use SATA drives if you don't need the extra features of SAS. SCSI isn't going away, it's just adapting.

Re:SCSI vs SATA

[gmezero]

Here's how I seperate SCSI vs SATA. I use SATA RAID setups for video workstations that need large drive space and cheap drives... and I don't care if the drive pops after a year of abuse.

I put SCSI in my servers (RAID or otherwise) when I want the box to run for years and years under heavy load and not have to worry about replacing drives regularly.

With SCSI, your paying for the quality control/quality assurance more than anything else.

From what I understand a good SATA drive has the same TTL quality as a good IDE drive, just faster performance.

My experience with 3ware

[dfn5]

I can say from my own experience with 3ware is that it sucks. We decided that we wanted to use S-ATA because we could get a lot of disk cheap. The problem was that these escalade cards didn't do parallel IO very well and by that I mean if one user is doing a long write operation the entire RAID array would go unresponsive to other users. For example if I created a large 20G oracle datafile the entire system would seem unresponsive until the operation completed. I wouldn't even be able to ssh into the server. And this was RedHat AS in case anyone wanted to know.

Moral of this story? You get what you pay for. SCSI should be used for servers.

To be fair, however, I was never able to determine if it was a result of using S-ATA, 3Ware or the linux device driver.

Re:Interesting that the 3ware offerings performed.

[archen]

Just as an aside and sticking up for 3ware. 3ware is one of the few companies that has good driver support for Linux and FreeBSD. As far as 2port SATA mirroring I always recommend 3ware as my first choice - performance is good enough.

Obviously if you're looking at a raid 5 solution, you're moving more towards higher end stuff, so it would be hard to recommend anything that performs poorly there. Rather dissapointing, but probably not that surprising since their SATA cards seem very similar to the ATA cards, so I'm sure they're throwing performance out the window there somewhere =/

waste of time and money.

[Anonymous Coward]

I am running RAID 5 in my computer right now.

Linux software RAID. Makes all this crap obsolete except for some specific cases.

I can have as many drives as I want, I can have hot swapability, I can have hot spares and all sorts of fun stuff.

Add LVM on top of that and you have a solution that is much superior then going out and buying any raid controller, except for the most fastest.

Linux software raid is actually VERY nice, I don't know of any OS that has better setup.

Re:waste of time and money.

[ltwally]

"Linux software RAID. Makes all this crap obsolete except for some specific cases."

So, you're saying that somehow your software RAID is calculating XOR bits and such without putting a serious hurt on your CPU and memory? Interesting.

"...I can have hot swapability..."

You're also saying that your motherboard has hot-swap capabilities built into it? Because it takes nothing short of specialized hardware controllers and BIOS's to be able to hot-plug a drive in. (ATA/SATA drive initialization is done during POST. Sure, Linux may do its own thing afterwards, but you cannot escape the legacy limitations of PC hardware.)

No offense... but seems to me that you're talking outta your arse, here. Software RAID offers only one thing in comparison to a good hardware RAID solution: price. In every other aspect hardware wins.. assuming your hardware RAID card isn't a POS.

Re:waste of time and money.

[Phil Wherry]

So, you're saying that somehow your software RAID is calculating XOR bits and such without putting a serious hurt on your CPU and memory? Interesting.

I'm not the original poster to whom you're responding, but the answer to your question is actually kind of surprising (it was to me, in any case).

At any given point in time, your system is in one of three states:

• partially idle (there's unused CPU and disk I/O capacity),
• CPU-bound (the CPU is fully utilized but there's disk I/O bandwidth available), or
• I/O bound (the CPU has spare cycles, but the disk can't provide data fast enough to put them to use).

I suppose that a heavily overloaded system could be both CPU and I/O bound, but it would require a mix of CPU- and disk-intensive processes that isn't usually seen in practice.

Let's ignore the partially idle case, in which there's ample disk and CPU to go around, as it doesn't really matter in this scenario whether the CPU or disk controller perform the XOR operations.

In the case of a CPU-bound process, you're going to incur the additional CPU overhead of the XOR operation. XOR is almost absurdly fast, particularly if the data is in the CPU's cache. I'm pretty sure that modern CPUs execute XOR on at least one byte per clock cycle. But let's say, for the sake of argument, that it takes three cycles per byte. On a CPU clocked at 3 GHz, you'd be able to perform XORs on one gigabyte of data per second if you ignore memory and cache issues. Given moderate memory bandwidth, you're also able to transfer over a gigabyte of data to or from the CPU per second. Given a more reasonable amount of data (say, one megabyte, to transfer), you'd be looking at a CPU impact of around one millisecond to perform the XOR. That's a 0.1% impact at most in a CPU-bound environment, and that's presuming you're doing a megabyte of disk I/O per second.

Now let's look at the I/O-bound case. Here, the CPU is sitting around waiting for the disk I/O to finish up. In this case, it clearly doesn't matter who's doing the XOR operations, since the CPU isn't fully utilized. PCI bus utilization is going to be increased by up to 100% (in the worst-case scenario involving drive mirroring; the worst-case RAID5 scenario is a 50% increase). A typical server's 66 MHz 64-bit PCI bus has a capacity of around 533 megabytes per second (PCI Express increases this dramatically, but let's stick with pessimistic examples for now). At the moment, a SCSI bus tops out at 320 megabytes per second, and those transfer rates are only achievable with at least four drives on the channel and an almost exclusively sequential I/O mix (the best-case numbers for a 15,000-RPM drive are about 100 megabytes/second). So there's generally bus bandwidth to spare.

You raise a number of other points in your note that are potentially issues (hot swappability, for example). But I've become convinced that the CPU/machine performance argument against software RAID really only made sense when CPUs/memory/bus bandwidth were much more constrained.

TRUE raid?

[fire-eyes]

All I care about is if these are 100% raid, unlike a seemingly increasing number of cards. In windows you might do alright, but anything else, look out.

In linux you will be treating such cards as a software raid array. Kind of defeats the point of buying "hardware" in the first place.

Wankers (the manufacturers).

Beware hardware RAID

[puke76]

Sure everyone buys a few spare drives.. but make sure you buy more than one RAID card. If the RAID card goes, unless you replace it with an identical make and model, you can kiss your data goodbye.

That's what I like about software RAID on Linux - you can mount the array on another linux box if you need to.

Have yet to see a good comparison between low-end hardware RAID and Linux software RAID..

Re:Beware hardware RAID

[tialaramex]

Anecdotal because I'm not paid to do this stuff..

We bought a 3ware controller for a large and somewhat valuable datastore (high resolution images of Alan Turing's personal papers which include all the text available elsewhere plus handwritten annotations, scribbled diagrams, etc.)

In the end I only used it as a fast and not particularly full-featured ATA controller, running Linux software RAID on top because it was not only _faster_ in every test I could think of, but also simpler to set up and maintain.

There aren't many published comparisons of this sort of thing precisely because the low-end (PCI card etc.) hardware RAID manufacturers lose, and that means they won't be renewing their advertisements in your publication any time soon. In _theory_ they should win if your application is both disk I/O and computationally heavy, and thus you can't spare any CPU to run software RAID, but I've never seen a benchmark that could demonstrate this apparently obvious result with real hardware.

Re:Beware hardware RAID

[justins]

If the RAID card goes, unless you replace it with an identical make and model, you can kiss your data goodbye.

If you are dumb enough to use RAID as a substitute for backing up, that is.

my 2 cents

[Ankou]

We have used 3 LSI 150-6 MegaRaid Cards and I must say that its the most increadible card / bang for buck you can get. Works perfectly in linux (Slackware 10.0 - 10.1 in our case), uses either the megaraid or megaraid2 (for those that want verbose information) right from the stock kernel compile. In each server we put in 6 Seagate SATA drives 250 GB each, totalling an impressive 1.2 TB total space. For under a grand (card + 6x 250 GB drives) you cant get a cheaper more reliable alternative. The thing aint slow either, consitantly get access of 100 mbps transfer speeds or more (hdparm tests / benchmarks). Initialization is almost instantanious, and while its doing the background inits (after the initial quick init), you can already access the entire contents of the full raided container. Do yourself a favor and grab one of these cards, you'll wonder why you stuck with the almost 3x price of scsi. Newegg.com has em for I think 290 bucks for the 150-6. Pay the extra money for the 150-6 its worth it. Optional battery packs available as well for the card.

The Article Never Explains What RAID 5 Is

[windowpain]

Now you could argue that a car review in Car and Driver doesn't bother explaining what a transmission does but RAID is several orders for magnitude more complex and esoteric.

There are so many different flavors of RAID it can be hard to keep them straight if you're not working with them every day.

Anyway there are good explanations of RAID here and here.

Re:The Article Never Explains What RAID 5 Is

[justins]

Now you could argue that a car review in Car and Driver doesn't bother explaining what a transmission does but RAID is several orders for magnitude more complex and esoteric.

Are you kidding?

RAID 5 can be explained in a few pages - the math, the implementation, the whole bit. Have you ever seen a technical drawing of a transmission? Modern slushboxes are about the most advanced mechanical engineering application that the average person ever comes in contact with (when they aren't at the airport).

You won't find an article that does most of the issues involved in designing and implementing a transmission justice. I know you just meant it as an example, but still. :)

Re:Comparison of Nine SATA RAID 5 Adapters

[killmenow]

It means that LINUX does NOT support them.

How you got modded Insightful is beyond me. Are you a troll? Did you RTFA? I didn't read it all either. But I read enough to catch this much: LINUX does support ALL of the cards in this review. Two of them (the Promise and RaidCore cards) come only in binary packages but the rest have Linux source available.

I, personally, would completely avoid any card manufactured by Promise or Highpoint as I've had crap luck with them in the past. They're just not very good cards, imho. And I'm not talking about their performance in Linux. I'm talking their performance in general. They're crap by my estimation regardless of platform. After losing data on my Windows 2000 box becuase of a crappy Highpoint card, I'll never buy another.

Anyway, your assertions are not even germaine. You point to the problem with "trick-BIOS" software RAID cards, which have been around for years and are not exclusive to SATA-RAID. They are shit cards, period...have been from the day they were made. Most of the cards in this review, however, are true hardware based SATA-RAID cards.

And, again, they all are supported on Linux. 3Ware, for example, has been a bastion of Linux support for ages.

As for the whole winmodem issue, who cares? What has it to do with a freaking troll blathering incorrectly about Linux not supporting SATA-RAID cards? Besides, the fact is, winmodems are NOT real modems. They're telecom interfaces, but not modems. You need software to make them modems. And I'm not talking about driver software to give access to the cards' functions. I'm talking software that has to implement the modem functionality itself...because the modem functionality doesn't exist on the "winmodem"...because it's not really a modem. Just because we now have linmodems.org and such to provide that software, it doesn't automagically make them "real" modems.

Re:Related Question

[LurkerXXX]

1,2) Tapes are of course way beyond what is called for in your situation. Tapes are for company servers where the data changes regularly and the system needs to be backed up quite often. Most of the data on your drive probably rarely changes, or changes slowly.

3) It can happen, believe me.

4) Home data can still be valuable and worth protecting.

5) Most of your data probably doesn't change that often, so DVDs would be fine. 100 DVDs can be had for around $50. That's not cheap for a student, but is probably worth trying to come up with when you think of how many hours you might spend trying to recreate that data. So:

1) Toss a DVD in to burn.

2) Go to class.

3) Go back to step one.

It won't be long until you have the bulk of your data backed up. Start with the most precious stuff.

6) Yes, a failing power supply can in some circumstances send a power surge through your system. It doesn't happen that often, but when it does, it can wreck a lot of your equipment. Plus a UPS will stop most but not *all* surges.

7) A good idea.

8) Use either DVDs or extra hard drives that are either offline or in another machine. Don't waste your money on tapes for your situation.

Re:Related Question

[Tassach]

I really don't want to burn 100 DVDs to backup my 500GB of data

Get two 250GB external USB drives. This is a very cost effective backup strategy.

External enclosures can be had for less than $30 and 250GB drives are under $140 each. Is your data worth $340?

Re:Interesting that the 3ware offerings performed.

[fragzillax]

Gotta agree on the 8506's being flaky. I could not get them to work reliably with 3 different mobo's (one was a supermicro, very nice server board), after calls to supermicro, 3ware, and much hair pulling, I purchased the Highpoint listed in the article, and have been very happy with it, especially considering the price delta for the 8506-8's... So I currently use the HPT, and have 2 8506's sitting in boxes that I'll never use because of all the trouble they caused. Maybe time to head out to the 'ol gun club...

Re:Interesting that the 3ware offerings performed.

[RFC959]

I am going to chime in with my damnation of 3ware's cards too. We have about 20 8500s and 8506s, with either Maxtor or Seagate drives. The things are horribly unreliable. Almost every day at least one array needs to be rebuilt. On a few occasions, we've even seen the controllers spontaneously lose an entire array - just poof, not accessible anymore and not visible through the administrative tools. Reboot and there's the array again.

Most of our support has been through a VAR (who sucks too, but that's a separate rant), but when we talked to 3ware and told them how we were using the arrays (for database storage), they immediately went, "Ooh...uhh...that's...not really a good idea..." Even they admitted that the SATA arrays are really for very light-duty use only. (I blame our old VP of technology, who always wanted to go the cheap route on everything.)

Oh, and if you want to upgrade the controller's firmware? 3ware tells you to boot off a DOS-formatted floppy. This is not enterprise-level stuff.

Not hardware RAID

[jgarzik]

Note that several of the cards reviewed in this review are not hardware RAID. SATA RAID is famous for being non-RAID controller + RAID software driver.

See my SATA RAID FAQ for a listing of the most common SATA chipsets which are sold as RAID, but are really software RAID (a.k.a. "fake RAID").

I'm also rather amazed that this wasn't mentioned in the review, but I admit I did not read all the of the 32 pages.

My RAID fantasy: 1394/USB2 Raid hub

[swb]

I'm sure that me and the few drunks I've managed to hoodwink with this concept are the only market for it, but why not a USB2/1394 hub that's actually a RAID controller?

The hub could present whatever defined logical volumes to the OS as additional mass storage devices on the hub, and a configuation application would be all that was needed since the logical volumes would be presented to the OS as generic mass storage devices.

I think this could have a real market; while the bus would certainly be a limitation in performance (perhaps 1394b would help), it:

* Wouldn't require a massive case with internal bays and power taps for the drives. (S)ATA RAID is cheap, but scaling beyond 3 or 4 drives is a huge challenge in all but the biggest cases. Using external connectors like 1394/USB2 would solve this easily.

* Wouldn't require any drivers beyond existing USB/1394 generic mass storage support. Yes, you would need a special application to configure the hub's logical volumes or to perform stupid RAID tricks, but beyond that you wouldn't.

* Portability to other systems, either in the event of a host failure or, since it doesn't require drivers and once configured, it could be moved to another platform that only supported the generic mass storage device.

* OK, speed would suck, but it's about adding big, reliable mass storage with a trivial interface, not about transfer rates. The hub could actually have distinct USB/1394 channels to individual ports, since it's not really a _real_ hub and the host OS wouldn't see the individual disks, just the defined logical volumes presented as mass storage devices.

I think this would be great for "backup" applications or other small-time/home user data warehousing (keeping your native DV-AVI files, DVD backups, CD backups, MP3 backups, yadda...) Tape is nice, but SDLT or LTO drives are expensive, as are the media. For $600 you can do better than half a terrabyte of RAID-5 disk, but you need almost an entire PC to house internal disks.

Given how cheap RAID cards are, I can't believe that merging RAID into a hub would be all that expensive, especially since you're actually removing a lot of the disk control logic from the controller.