20TB or Bigger Hard Drive Array

If you're willing to spend that kind of $$, why not build your own server and that way you won't be limited to 16TB?

I just built an unRAID server with space for 10 data disks, @ 2TB each that's 20TB total. If I bumped it up to 3TB drives I could have 30.

You could also save a lot of money by using 5400 RPM drives, they are plenty fast for what you want to do.

I'm a bit curious now. There clearly aren't many 4 tb hdd's out. The only internal 4 tb newegg has is $370. There is this external drive though, which sells for $250. Couldn't you just buy 5 of those, take them out of their cases, and put them in a bare Drobo S ($600 online). That's $1850 vs. $2300.

Make a server.

Buy a board and some PCI raid cards for SATA.

Install in a case.

You can have 50TB if you wanted.

You can spend considerably less and achieve the same thing.
You can buy a rackmount or tower case and throw 20+ 20TB drives utilizing unRaid, FlexRaid, etc... and give yourself considerably more options and flexibility then what you listed.

It has 4TB Barracuda XT inside.

Only if you are limited by space.

Cheaper to do 2x2TB drives.

And those drives need to be on the approved HW list for the NAS/Raid card you intend to use. You can't just buy anything.

Drobo's are slow as dirt - run away from them. If you want a standalone NAS then look at Synology or ReadyNAS.

+1 I couldn't say it any better, been running now for almost a year and I loving every minute, as well as wife and wallet too

Btw, I had been looking into the Drobo S as well, but I just read this review. Not sounding very good. Transfer speeds were very slow and rebuilding the array took ages.

Here's a cheap driveless 4 bay for 180$

Drobo S supports up to 3TB drives (10TB usable loaded with 3TB drives). Its a very good device that is easy to manage and refined. It offers basic redundancy, hot-swap expansion and the ability to mix-and-match drives. The ability to mix and match drive brands/sizes makes it a great value.

I think you need to research your options and re-evaluate your real needs before you set the budget. The requirement of 20TB of storage with high throughput requirements wont be met by a home-grade solution. Your stepping into the world of "Business Class" so start by looking at products marked to that segment. There is additional processing "overhead" when raid's come into play, and soho devices typically suffer in the throughput department compared to a traditional usb 3.0 drive.

The Drobo Pro or 8 Bay for Business is a good start :
http://www.bhphotovideo.com/bnh/cont...=REG&A=details

Loading it up with 3TB would give you 21TB (18TB usable)

I cosign the user above who said build your own, but only if you have the patience and skillset to go with unRAID/Linux.

Look at the Synology DS1511. It is expandable with additional drive cages.

- Sans Digital 8-Bay SATA to USB 3.0 JBOD Tower Storage Enclosure TR8U+B, $350
- 8 x 3TB HDD (~$180 each; just buy only necessary at first, the price will drop quickly)
- FlexRAID

Here is just one of the problems with RAID5/6. You need to determine what you want to buy, and buy them all the same. But HD pricing is always evolving. Locking yourself in to a certain drive size, and getting the best $/TB, don't go hand in hand. I started my WHS server several years ago with a few old leftover 250GB & 400GB drives, and soon added some new 1.5TB drives (which were the biggest at the time). Since then, all the small drives have since died, and now I have about 40TB worth of drives, comprised of those 1.5TB drives, but now mostly 2TB drives. I have the flexibility to add whatever size drive is the best value at the time, and the server has gradually grown over time, as needed. No sense in buying more storage than you need at the time, because it will likely be cheaper in the future (especially now).

Hardware RAID is so much more restrictive. It's ironic to me that people look to RAID as a solution to protect their data, then choose a method that scrambles their data across multiple disks, making it nearly impossible to recover should something go terribly wrong. RAID5/6 is a great solution for a high load multi-user enterprise where the extra bandwidth is needed, and they have the budget and staff to keep it maintained. But IMO, it's not a good solution for a home media server. A RAID4 based solution such as unRAID, FlexRAID, SnapRAID, etc., is much more cost effective, energy efficient, easier to upgrade, easier to migrate, and easier to recover from fatal errors. And for the average user, it's safer. You can always get data off of a drive just by connecting it to another computer.

+1. I've been running an unRAID server for over four years and I wouldn't think of switching to something else. For a home media server it does the job quite nicely. I can set up shares for drive pooling and I can access it from any PC or media player on my network with no limitations. Upgrading is easy and completely painless. My server currently consists of fourteen 1.5TB drives and one 2TB parity drive, for a total of just over 20TB of useable storage. I will soon be upgrading it with four more drives as I have an extra SATA backplane that I'm not using with four good slots (the 5th slot is a bit flaky, which is why I took it out of service a while back). I've got quite a few 750GB drives sitting idle that were part of the original configuration before I swapped them all out with 1.5TB drives. With today's drive prices I figured I might as well make use of what I have on hand, which is another reason why I love unRAID. It's not hardware specific like some RAID setups.

If I lose a drive then I can recover the data via the installed parity drive. If the parity drive dies then I can simply install a replacement and rerun the parity check to restore it. Only the drives in use are spun up for access and they all spin down when not used. You can use as few as three drives (two data and one parity with the freeware version) or as many as 20 data drives, depending on which license you purchase. I like that it runs from a USB thumb drive so you don't have to sacrifice any disc storage to install the OS.

There's a great support forum and a wiki that provides answers to any questions you might have as well as complete setup and operating instructions. I also like that you can interface with the server main menu using a web browser on any PC connected to the network.

+3 for unRaid - I've changed drive capacities several times over the years and would have been stuck if I'd gone the traditional route. Today you're thinking 20tb will be all you'll ever need, but I can almost guarantee that in a couple of years you'll be wishing you could swap out those 2tb drives for 6tb ones. (True story, I bought my first HD way back in the day. It was a 30mb one and I spent the extra $$ because I knew I'd have this one forever-there was no way I could ever hope to fill that bad boy up!)
That's the cool thing about unRaid. Load her up with 2tb drives, and when you start to run out of room and prices fall you can swap out with larger drives one at a time.

But the downside of unRAID is that with their 20 drive limit, you can reach a point where replacing smaller drives with larger ones is the only way you can get more space (though considering they only support one parity drive, I wouldn't even want to push it to 20 data drives). I agree that you can be surprised at how fast your storage needs can grow. I strongly considered unRAID a couple years ago, but ultimately went with FlexRAID instead. At the time, it wasn't the drive limit that swayed me, I couldn't imagine needing more. But as it turns out, I'm now at 21 drives, so it's a good thing I went a different route. It's good for a medium sized system, but it's not that hard to outgrow it.

I'm using WHS (v1), with a combination of motherboard SATA ports (6), a SiI3132 PCIe card with two eSATA ports (which accept port multipliers), a SiI3124 PCIe card with four eSATA ports (which accept port multipliers), and a Supermicro SASLP-MV8 with 8 SATA ports (which could be expanded with the HP SAS expander). I'm currently only using two port multipliers on the 3124 card, but can add more as needed. So ports aren't the issue. WHS v1 has a limit of 31 pool drives (+ the default D drive), though I could expand beyond that with drives outside of the pool. But I'll cross that bridge when I get there. I expect it'll be a couple years... by then I probably will have upgraded the OS.

There are plenty of options to get as big as you want. Many ways to skin this cat.

No, it's not the only way. Build a 2nd system. Although I personally can't fathom what exactly I would do with a system of 20+ HDs (likely 20-60TB total storage capacity), I can understand needs under some circumstances outside of an enterprise scenario. But a requirement of that many drives that must be contained within the same system seems unlikely. If you're going to spend several thousand on drives, spend a few hundred more and get a second system.

For instance, if you have 20 2-TB drives, 10 of which are movies, 10 of which are television, split them in half moving the TV to a 2nd server. You then can grow each 10 more drives. If you're not using it for HTPC content, I'm sure there's some type of logical division of the type of data to split it across multiple systems.

That's true. Personally, if I had a choice of one system with 40 drives or two with 20ea, I'd take the single system. But that is an option.

Second system means second license for unRaid. Ability for Flexraid to manage more then one pool and/or more then one parity drive would make it more valuable in a 20 drive system.

Maybe an option to look into is Windows 8 Storage Spaces with its UnRaid type of storage set-up.
I dont believe there is any limit to how many hard drives you can use with it.