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I store users' roaming profiles and home directories on a server running Windows SBS 2003. The server's storage is a SATA RAID-5 (3ware rocks!). SBS backs itself up to disk weekly, which I occasionally transfer to an external hard drive for DR purposes. The profile and home directories are separate SMB shares because the share containing the roaming profiles is configured to disallow client-side caching (which causes problems with the user profile loader on older versions of Windows and maybe even Vista). The shares are accessed via MSDfs because some day I'd like to replicate them to a second server and want any accesses or fail-over to be somewhat automatic (again, for DR purposes). I use Group Policy to move each user's "AppData", "Contacts", "Desktop", "Documents", "Downloads", "Favorites", "Links", "Saved Games", and "Searches" folders to their home directory. In my scheme, "Music", "Pictures", and "Videos" are sub-folders of "Documents", for backwards compatibility with Windows XP. I've also configured Volume Shadow Copy, which allows users to retrieve older versions of their files without needing to bother me about restoring them from archival backups, and deployed Certificate Services on SBS. Each user's enrolled in the domain PKI, so they can encrypt their caches as well as any of their files.

From the users' perspective, everything is automatic: They log in, work with their files, and log out. If they are out of the office, they'll get a warning about working with a cached copy of their profile, but that's about it. When they return, they'll get prompted to sync any conflicting changes made while offline. Windows has featured CSC (also known as "Offline Files") for some time, but it's only gotten really stable in Windows Vista. A few programs don't really play well with CSC but nothing that's a deal-breaker (like Firefox or Skype storing database stuff in the roaming version of the AppData folder when it really should be in local version instead, but I kind of brought that on myself when I redirected it to the network share to start with).

I need controller(s) for 12 SATA drives, not PATA.

Their SATA controllers (other than a cheaper one that's only 2 ports) are really expensive. Unless I were transferring a lot of data frequently among multiple drives on a single card, I'd be better off just buying a few 2 port SATA cards for over $150 for every 4 ports, plus the cost of the card itself.

3ware makes a controller that can run twelve IDE drives per controller in RAID. Assuming you can get 4 controllers per box, a network of 30 systems should be able to run the drives. Custom enclosures would have to be built to hold them all and you might want to buy old ATA power supplies to spin them up, but it is feasible. Using that number of cables could be a logistical nightmare for airflow. This is the only supplier of cards that run 8 or 12 IDE drives.

Also, if you're concerned about Linux block device performance, look at the various kernel tunables. On a single drive, such as those Seagates, I can get extra ~10MB/s. On RAIDs and LVM volumes, the differences can be much higher-- more than twice as fast, in some cases. There are a few parameters that make a difference, and many values you might want to try for each. I have a script iterate through the various permutations, running IOZone on each, so I can see what does best for read vs. write and large vs. small file performance. But I can't release it just yet (employer makes 100% of income from Open Source; employer hates Open Source). Anyway, somebody out there can do better than I, I'm sure :)

This discusses the tunables you'd want to check: http://www.3ware.com/KB/article.aspx?id=11050

Note that these do NOT apply only to 3Ware controllers. And the differences in performance can be massive.

the build in ports are on the pci-e bus as the 5000x chip set uses pci-e lanes for part of the chipset to chipset link and most pci-e hardware raid cards are x4 with x8 for cards with more ports http://www.3ware.com/.

also the 8800 cards are slowed down by a x8 pci-e slot.

pci-e video in cards may use 1-4 lanes also you may want a pci-e based firewire bus.

Had I used RAID5, I would have 1,500 GB and it would not have been easy to upgrade. I have ran out of room and I am adding a couple of 750 GB drives.
If you use a linux server and LVM, losing one drives loses everything.

Case: Koolance PC4-1036
Motherboard: Tyan Thunder n3600M
Raid: 3ware 9650SE-24M8
Hard Drives Seagate 750GB
RAM water cooled
Power supply: Koolance 1200W

How did you get to 3TB in a home PC? I know a couple of boards that support 6 onboard SATA connections, but I know of no single chassis that can hold them, nor any reasonably priced RAID 5 controller that can be run without a 64bit PCI slot.

64-bit PCI isn't exactly out of the home arena anymore, and even if it were, it's possible for 64 bit cards to work in the old 32 bit slots. In fact, I've had a 3ware 7506-4LP controller in one for a few years now. They also have 8, 12, and 16 port models for ATA, SATA, and SATA II.

As for mounting the drives, if you wanted them in the same chasis as the rest of your rig, you should probably have selected nothing less than a full size tower where 8 or more internal 3.5" enclosures isn't uncommon (and adequate cooling can be available). You can also find mid-sized cases to accomodate the 6 that you mentioned, or more. Otherwise, you might increase internal mounting capacity a bit with something like 3ware's drive cages, or look at an external firewire cabinet - but now you're leaving the realm of "cheap". Of course, if you're buying 8 or 12 SATA drives, you weren't really in it to begin with...

No, I don't work for 3ware. I've just been really happy with a few of their products.

How did you get to 3TB in a home PC? I know a couple of boards that support 6 onboard SATA connections, but I know of no single chassis that can hold them, nor any reasonably priced RAID 5 controller that can be run without a 64bit PCI slot.

64-bit PCI isn't exactly out of the home arena anymore, and even if it were, it's possible for 64 bit cards to work in the old 32 bit slots. In fact, I've had a 3ware 7506-4LP controller in one for a few years now. They also have 8, 12, and 16 port models for ATA, SATA, and SATA II.

As for mounting the drives, if you wanted them in the same chasis as the rest of your rig, you should probably have selected nothing less than a full size tower where 8 or more internal 3.5" enclosures isn't uncommon (and adequate cooling can be available). You can also find mid-sized cases to accomodate the 6 that you mentioned, or more. Otherwise, you might increase internal mounting capacity a bit with something like 3ware's drive cages, or look at an external firewire cabinet - but now you're leaving the realm of "cheap". Of course, if you're buying 8 or 12 SATA drives, you weren't really in it to begin with...

No, I don't work for 3ware. I've just been really happy with a few of their products.

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.

BTW, regarding one of your other posts, I own an old 3ware 6410, which you allege is software RAID, and I distinctly remember going into its BIOS to create and initialize its RAID5 array."

Correct, you setup the array in the BIOS, but it will not build or rebuild the array until the OS is booted and the driver is loaded:

From the user manual of he 7000-8000 user guide (pdf) found on page 42:

11 Press F8 to save your configuration and reboot the system.
The rebuild will start within a few minutes of the 3ware driver
loading, once the operating system has booted.

I know this is from a later model, but I am certain it is the same way for your controller, they didn't start hardware RAID until the 9000 series.. (I have talked with their engineers extensively and worked with their hardware in real life situations for years).

I'm sorry but I won't be spending any time pouring over code to find where they do the calucations, but that would be a great place to look, any coders out there wanna give it a try?

http://www.3ware.com/support/windows_agree.asp?pat h=/download/Escalade7000Series/7.7.1/3w-xxxx.tgz

Just click agree to get the 7000 series linux 2.4 source.

These 3ware cards are definitely hardware RAID. You are spreading FUD.

The parallel card is the $110 on newegg.

From Newegg StorSwitch switched architecture delivers the full performance benefit of Parallel ATA's pointto- point architecture up to 133MB/sec per port On-board processor provides true hardware-based RAID and intelligent drive management functions BIOS set up utility and 3ware Disk Management (3DM) web-based management software Bootable array support for greater system fault tolerance

http://3ware.com/products/parallel_ata.asp

Sorry, I don't know about the whole line, but the 7500 and 8000 series are definitely hardware. The 7500 page specifically talks about the hardware XOR engine:

http://www.3ware.com/products/parallel_ata.asp

The 8000 page also says: "True hardware RAID protection for all your valuable data"

http://www.3ware.com/products/serial_ata8000.asp

Not to beat a dead horse, but the Escalade 7000/8000 confiuration manual specifically discusses using the BIOS utility (invoked through Alt-3 during boot) to create/modify arrays:

http://www.3ware.com/support/UserDocs/7000IG_04290 3.pdf pages 25-27

Where do you see that any of their products are software?

Derek

Sorry, I don't know about the whole line, but the 7500 and 8000 series are definitely hardware. The 7500 page specifically talks about the hardware XOR engine:

http://www.3ware.com/products/parallel_ata.asp

The 8000 page also says: "True hardware RAID protection for all your valuable data"

http://www.3ware.com/products/serial_ata8000.asp

Not to beat a dead horse, but the Escalade 7000/8000 confiuration manual specifically discusses using the BIOS utility (invoked through Alt-3 during boot) to create/modify arrays:

http://www.3ware.com/support/UserDocs/7000IG_04290 3.pdf pages 25-27

Where do you see that any of their products are software?

Derek

Sorry, I don't know about the whole line, but the 7500 and 8000 series are definitely hardware. The 7500 page specifically talks about the hardware XOR engine:

http://www.3ware.com/products/parallel_ata.asp

The 8000 page also says: "True hardware RAID protection for all your valuable data"

http://www.3ware.com/products/serial_ata8000.asp

Not to beat a dead horse, but the Escalade 7000/8000 confiuration manual specifically discusses using the BIOS utility (invoked through Alt-3 during boot) to create/modify arrays:

http://www.3ware.com/support/UserDocs/7000IG_04290 3.pdf pages 25-27

Where do you see that any of their products are software?

Derek

--Pat

Not a "Super Card", but 3ware is the brand you want to see : http://www.3ware.com/products/index.asp

I think they have a model up to 16 drives, but you should look at the 9550SX-8LP, 8 drive ATA controller.

For SATA : model 8506-8
Up to 8 Serial ATA
0,1,10,5, JBOD

Departmental Servers, Security and Surveillance, Disk-to-Disk Backup...Raid 10 on two arrays looks good to me....

For max size, I think would opt for a RAID5 on 7 disks and keep the 8th drive as a "hot-remplacement" for the soon to be faulty drive...

7*500Gig/RAID5 should give you 3 Tera with (some) data protection and an hot-plug replacement...

Anyone cares to counsel ?

I've been putting together the specs for such a beast. I decided to go with SATA for cheap drives and "SATA-II" (or whatever you want to call it, since there isn't a standard name for NCQ and 3.0Gbps support) for future-proofing.

1) The natural first choice was 3ware. 12 port SATA-II controller (9550SX-12), for about $800. 3ware products are very well supported on Linux. The only downside is that it's a PCI-X device (this is NOT "PCI Express"!), and PCI-X busses are generally only found on very high end motherboards for servers and workstations. Any athlon motherboard or single-processor opteron board claiming to have PCI-X is lying, they really mean PCI express (AMD chipsets did not support PCI-X at all until around the time dual opteron motherboards were being created)

So since I didn't want to spend $500 on a motherboard that had built in scsi raid, support for 16GB of ram and dual opteron processors just to use that $800 card, I looked around some more...

2) And found a serious contender, the 12 port Areca 8x PCIe ARC-1230 (also about $800). While most low end motherboards don't provide an 8x PCI Express slot, they DO provide a 16x slot which will work just fine for this card (after all, this will be the fileserver, so a motherboard with crappy built in video will do, we're not playing Doom 3 here). Linux drivers are provided as source, even including a kernel tree patch which will build the driver into the kernel rather than as a module, making booting directly from the RAID controller easy.

Slap the Areca into Tom's Hardware's 37 watt computer (motherboard has built in GigE, but pentium-Ms are 32 bit processors, making giant files/filesystems a pain. An Athlon 64+cheap mini-ATX can be had cheaper, but uses more power), add in a stack of 10 watt 400GB WD Caviar Raid Edition 2 drives, and you're set for a very low power fileserver with a lot of storage.

Now, my turn to "ask slashdot":

Where do I get a 250-300 watt powersupply with 12 SATA power connectors?

Alternatively, do the SATA drive cages (like 3ware's RDC-400-SATA (pdf) have their own SATA power connectors built in and use standard molex connectors on the outside? Do I need special cages to support 3Gbps drives (ok, not a serious problem for now, but futureproofing)? 3ware's website says it'll work, their product PDF doesn't.

I've been putting together the specs for such a beast. I decided to go with SATA for cheap drives and "SATA-II" (or whatever you want to call it, since there isn't a standard name for NCQ and 3.0Gbps support) for future-proofing.

1) The natural first choice was 3ware. 12 port SATA-II controller (9550SX-12), for about $800. 3ware products are very well supported on Linux. The only downside is that it's a PCI-X device (this is NOT "PCI Express"!), and PCI-X busses are generally only found on very high end motherboards for servers and workstations. Any athlon motherboard or single-processor opteron board claiming to have PCI-X is lying, they really mean PCI express (AMD chipsets did not support PCI-X at all until around the time dual opteron motherboards were being created)

So since I didn't want to spend $500 on a motherboard that had built in scsi raid, support for 16GB of ram and dual opteron processors just to use that $800 card, I looked around some more...

2) And found a serious contender, the 12 port Areca 8x PCIe ARC-1230 (also about $800). While most low end motherboards don't provide an 8x PCI Express slot, they DO provide a 16x slot which will work just fine for this card (after all, this will be the fileserver, so a motherboard with crappy built in video will do, we're not playing Doom 3 here). Linux drivers are provided as source, even including a kernel tree patch which will build the driver into the kernel rather than as a module, making booting directly from the RAID controller easy.

Slap the Areca into Tom's Hardware's 37 watt computer (motherboard has built in GigE, but pentium-Ms are 32 bit processors, making giant files/filesystems a pain. An Athlon 64+cheap mini-ATX can be had cheaper, but uses more power), add in a stack of 10 watt 400GB WD Caviar Raid Edition 2 drives, and you're set for a very low power fileserver with a lot of storage.

Now, my turn to "ask slashdot":

Where do I get a 250-300 watt powersupply with 12 SATA power connectors?

Alternatively, do the SATA drive cages (like 3ware's RDC-400-SATA (pdf) have their own SATA power connectors built in and use standard molex connectors on the outside? Do I need special cages to support 3Gbps drives (ok, not a serious problem for now, but futureproofing)? 3ware's website says it'll work, their product PDF doesn't.

With RAID, you still have a single point of failure. Instead of it being your hard drive, it is now your RAID controller. So what is the advantage?

Since a RAID controller doesn't have moving parts, is it less likely than a hard drive to fail?

The best option for real hardware SATA (or IDE) RAID in Linux is 3ware, bar none. Their drivers have been in the official Linux kernel since the early 2.4 days, and they just work. Highly recommended.

Why real hardware RAID? Say, for example, your boot drive goes out in a software RAID configuration. Your system is suddenly unable to boot, requiring manual intervention for a rebuild. With hardware RAID, the BIOS built-in to the card handles things smoothly and your system can boot without a problem.

3ware

Just a suggestion but if you are looking for a good SATA RAID controller take a look at what 3ware has to offer. Their 8000 series controllers are very nice. 3ware has always done it's best to work closely with the FOSS community, Adaptec, not so much.

Just a suggestion but if you are looking for a good SATA RAID controller take a look at what 3ware has to offer. Their 8000 series controllers are very nice. 3ware has always done it's best to work closely with the FOSS community, Adaptec, not so much.

Yes, it would be great to add cache to SATA drives. Or wait, how about an onboard CPU to offload the processor? Oh and wait, let's add RAID5 xoring too! Oh and command queuing, elevator sort seek optimizations, and all the other nice SCSI stuff.

If only someone made a product like that which supported many drives and most major OSes including linux...

If only I could find such a thing under this rock where I've been living the last few years!

This happened to me. The card was sorta still working... could read, with lots of errors usually recoverable, but writing was flakey.

Luckily, even after about 3 years, 3ware (now AAMC) was willing to send me a free replacement card. They answered the phone quickly (no long wait on hold), they guy I talked with knew the products well, and he had me email some log files. He looked at them for about a minute, asked some questions about the cables I was using, and then gave me an RMA number.

The new card came, and my heart sank when I saw it was a newer model. But I plugged the old drives in, and it automatically recognized their format and everything worked as it should.

This might not work on those cheapo cards like Promise that really are just multiple IDE controllers and a bios that does all the raid in software. Yeah, I know they're cheaper, but the 3ware cards really are very good and worth the money if you can afford them.

The Promise controllers are SHRAID, which is my own non-standard acronym for Software w/ Hardware-assist RAID or SHitty RAID in less polite company. And the "promise" of true redundancy is a charade (rim-shot, please). Basically, you have all of the disadvantages of software RAID - the need to manually configure bootability of both drives (assuming you're running RAID 1 or RAID 0+1 - if you're running RAID5 or JBOD it's an even bigger pain), plus the need to have specialized drivers on the OS, etc. These controllers (Promise, Highpoint, etc.) should be avoided like the plague for technical reasons alone.

Good, relatively inexpensive IDE and SATA RAID can be had with 3Ware Controllers. 2-drive models start around $140, and they support up to 12 drives on their more expensive controllers. The drives appear as a single physical device to the O/S, whether it's Windoze, Linux, BSD, DOS 3.1, etc.

my tower has still tons of unused 5.25" bays

I have been envisioning a personal hot swap RAID array that will fit into, at most, two drive bays for a long time. The SATA RAID stuff from 3ware have been tempting but require a pretty big case and add a lot of fan noise. A bit loud for my family room.

Get a decent controller card, and the firmware will actually optimise the head movements to increase read performance. Think about it - if you've got the same data on two drives, why not have each drive read only half the file and thereby return the whole file in half the time?

That's wrong, they work well in 32 Bit slots, too. See http://www.3ware.com/products/pdf/Motherboard_comp atibility_list.pdf

We have very good experiences with 3ware SATA cards, too. (In a 32 Bit slot.)

Some people have had a surprising level of success uing the software raid potential of Linux to do this for some time, getting prices as low as $0.60US per GB.

Some slashdot articles on some previous attempts:
Bulk Data Storage For The Common Man?
Home-brewing a 1.2TB IDE to Firewire Monster

Books on it:
Managing RAID on Linux

Even applicable controller hardware:
LSI Megariad 150-6
3Ware 9000 series

And soon to be applicable storage hardware:
Hitachi Announces 400GB Hard Drive

• Find any tall beige-box case. ($150)
• Find 9 good 250g Serial ATA drives. ($100 each = $900)
• Get an 8-port serial ATA hardware RAID controller like these ($300)
• Get a good 400-500W power supply ($200)
• Any motherboard and CPU will do ($200)
• Spend a few extra bucks on gigabit ethernet ($50)

Rip all your CDs as FLAC so that (1) you never have to rip them again (it's lossless), but (2) it's half the size of saving WAV files

At least that's what we've done with our 68,000 CDs we have here.

3 Ware 12 drive RAID card

I I havn't calculated the per MB cost of all the large sizes. someone with more time please do this.

What will make this perfect is removeble drive kits (They require an external 5.1/4" bay for each 3.1/2" drive. Some even have little activity LEDs) and a server case with 12 external 5.1/4" bays.

Do read up on some of the fundamentals of RAID: Everything you need to know (and lots you don't) is probably at least mentioned in the PC Guide on RAID. Look through that. Things like hot swap and hot spares are important to understand. Finally, you should remember to check compatability. Unfortunately, I for instance have not been able to find much of anything in the way of controller cards that is compatable with OS X (except the obvious, the XServe RAID). So I have something set up on a BSD box in my server closet that I then link to, more like a storage appliance. Happily, the 3ware cards and many others are now compatable with a wide variety of *nix and BSD flavors along Windows, but do check to make sure.

Last but not least, remember this!: RAID is *not* a backup solution, but an highly redundant onsite storage system. Have another form of backups, even if it is just a RAID 1 off site, or DVD-Rs, or something. If a disaster happens (thieves, fire, nuclear destruction, John Ashcroft) on site storage won't save you.

2 of these controllers: http://www.3ware.com/products/serial_ata9000.asp with this case: http://www.chenbro.com.tw/product/product.jsp?p=3& s=304&pid=62 and you can have SATA 250GB X 24 = 6TB of storage. That or buy a bunch of 9.1GB SCSI drives, and a lot of arrays - and you'll end up with a fairly cheap storage solution, and one heck of a horrible power bill.

I've recently been given a similar task in constructing a new fileserver, and when I came across the products available from 3ware I knew I found the answer. Their raid cards are rock-solid, work exceedingly well with linux and come in almost any configuration you could ever ask for. The real kicker is that they're built around supporting inexpensive PATA and SATA hard-drives, rather than high-end SCSI. http://www.3ware.com

Then for a case to put all those drives in, P-link offers a few that do a decent job. The quality of these cases is somewhat mediocre, but the price is hard to argue. Just don't buy swappable drive bays here, as those can be found for half the price anywhere else. http://www.plinkusa.net/web5101.htm

3Ware Escalade -- http://www.3ware.com/

The Escalade 8506-12 has 12 x SATA ports onboard. Full hardware implementation; appears as a SCSI host adapter to the OS. Drivers and management utilities for MS-Windows, Linux, and FreeBSD. It will even email you if you have a disk failure.

3Ware was one of the first ATA RAID vendors to put a driver in the Linux kernel, and it was a fully-supported, GPL driver from day one. Rock solid stuff. Good tech support, too.

Highly recommended.

http://www.3ware.com/products/serial_ata.asp/

and the 3ware escalade 7506-12 @

http://www.3ware.com/products/parallel_ata.asp/

I am personally done 11x250 (need a hotspare :p)

They work quite well, have about 50TB in the field.

http://www.3ware.com/products/serial_ata.asp/

and the 3ware escalade 7506-12 @

http://www.3ware.com/products/parallel_ata.asp/

I am personally done 11x250 (need a hotspare :p)

They work quite well, have about 50TB in the field.

I bought a case from http://www.servercase.com/, a 3Ware RAID Controller and 8 200GB IDE drives. I've got 1400GB of usable space in RAID5. It runs Linux with Samba and NFS. I also use it for a MythTV Backend.

Unfortunatly, once you have all this space, you WILL find a way to use it all and need more. I put this system together about 10 months ago, and it's at 85% capacity now. I'm preparing to build a new server with 12 250GB drives, to have just over 4TB between the 2 systems.

I took a nice 8 discs and a pair or 3ware Escalade 8506-4LP (max 2TB/array, so I have two arrays in RAID0)

The system runs on debian and provides Fileserver for a small video-editing company.

you can find a test of the hdd here

For the case, I took the Cooler Master STC-T01, a bit overkill, but I was a anxious of overheating ...also, it provides room for another 4 disks, but I will need another psu to power 12 disks....

The disks are quite silencious, and the 3Ware card allow for staged disk spin-up, so I was able to run it all on only 1 PSU.

Overall, that makes a 3Tb Fileserver for 4500Euros (including a cheap AMD XP 2400 + 1 Gig ram and Gigabit ethernet), which is quite nice if compared to NAS appliances offered elsewhere.

Of course I don't have the whole collection of utilities to manage the box that comes from major vendors, but Webmin is quite up to the task...

Also, having 8 disks in two RAID0 offers no security/redundancy whatsoever, but I was just asked for a giant fileserver, not a Disaster Recovery implementation 8)

With HD space coming so cheap, I think a dedicated RAID box would work as a storage solution. DVD's are a pain, I'm assuming you want to store large volumes of data, so people will say get a tape backup. 1. They're expensive and 2. They're small. Even with a 200GB tape compressed to 400GB... You're still not anywhere near 1.6TB or even 800GB (since we don't know what type of data he might be compressing, I'll just go with an even 2:1).

Oh yea, Buying PATA drives in bulk. If you do this, assume failures will happen in bulk and purchase extra's accordingly. 3Ware, according to their website (and as far as i know) make the only 8 & 12 port RAID cards around. Couple that with a cheap full tower (or a badass midtower) and throw in 12+ HDs.

Since you considered DVDR, I'm assuming this doesn't need to be online 24/7. This is not a problem since it's storage, feel free to power down your raid box. This saves the headaches of hardware failure, power surges, accidentally hitting the delete key, etc.

In deciding Tape vs RAID, the key factor should be: Do I want my data spanned across several tapes. If you can get 4:1 compression or better, by all means consider the tape drive, but with a big enough tower, you could get >3TB + redundancy + hotspares. My only RAID5 problem is that even with 1.6TB of data, you lose two drives and you're toast. {--that should be your second deciding factor. It's a scary thought.

Avoid Promise - seek 3ware.

3ware has great support and superior benchmarks to the Promise, et al. equivalents.

Do your own homework/research, but 3ware appears to be the clear performance leader.

Head on over to 3ware and select the RAID controller you need... I've got a 7506-4LP in my server at home and it simply kicks ass.

Obligatory 3ware post...

www.3ware.com

does raid in hardware unlike most (all?) promise, yadda yadda, software raid faster than battery-backed hardware, yadda yadda yadda, do you really need hot swap? if not, software raid, yadda yadda

using Promise "to give you headaches" Controllers. If you're going to use (S)ATA you really should give 3-Ware a look.

If you want a RAID solution that is not absolutely awful without spending loads of money on SCSI hardware, the only way to go is 3ware. They are the only ATA hardware RAID solution (which means dedicated hardware on the controller is responsible for RAID operations, not some stupid kernel-space driver) and offer controllers with either parallel or serial ATA interfaces. I myself am using two Escalade 7006-2 cards (32-bit PCI interface, parallel ATA, two disks per controller) under FreeBSD and they are excellent. Performance is good, disaster recovery is flawless (they support background mirror rebuilding), and compatability is perfect.

They are also quite cheap. If you go to Monarch Computer, you can find the model I have for around $110 with free shipping.

I know it's hard to trust advice from Slashdot, but this is the best way to go. As many others have pointed out, RAID-1 is the obvious choice for personal uses. And always stay away from software RAID. Whether it's the Linux kernel RAID subsystem or Promise, Highpoint, etc. (these "RAID cards" are in fact software), software RAID sucks and will increase the chances of data loss, not reduce it.

I have a blog entry that talks a little bit more about this.

From my understanding the latest 3ware 9500S-12 cards will support up to 4 controllers. Now thats quite excessive, bandwidth for 48 harddrives would choke any PCI-X subsystem out there.
9500 SATA Controller

I use 3ware 9500S-12 on a dual opteron myself.

Actually a raid1-card for two ide-drives is quite affordable.