arcsine

OK, I get it, RAID on the desktop is dumb, but...

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I read the article on the RAID on the desktop craze, and largely I agree, but now I'm a bit lost in what exactly I should use as a primary disk in an entry-level A/V workstation. I had originally thought that my best bet would be to use Intel's new "Matrix RAID" config to make myself a 16GB RAID0 volume for OS/Apps, and JBOD out the rest of the space on two Raptors for writing short recordings to. However, this appears to be a waste of money for the performance increase (even though the graphs in the "seductive acronyms" article appears to indicate that going from a single disk to 2-disk RAID0 ups the high-end drivemark from 580 to about 650). Now, I'm torn between two options:

1. Use the ICH6R SATA controller to hook up a single Raptor 74GB, or the above with 2 Raptors.

2. Buy the Seagate ST373405FC that a friend can't return from his company's failed Fibre Channel enclosure, one of these, and a QLogic QLA2200 for $50 on EBay.

3. Buy 4 Seagate ST380817AS, hook them up to a secondary SATA RAID controller, and run them in RAID0+1.

Fibre Channel on the desktop sounds as absurd to me as RAID0 sounds to the reviewers. All four options are in my price range, and actually the FC is cheapest, considering I can get the disc for $100, the HBA for $50 on EBay, and the 9-pin to SCA adapter for $20. Theoretically, I could even use the money I save to buy a mobo with 64bit/66MHz PCI slots. It looks to me like the U160 version of the FC drive in question scored way low as compared to the Raptor, however.

Here's my prospective parts list, if it makes much of a difference:

Processor- 3.2GHz Prescott LGA775

Mobo- Supermicro P8SAA

Memory- 2xCrucial 512MB DDR2-533

Hard disk(s) - ???

Optical drive- Teac DVW58GA

Video- Matrox G550 PCI

Sound- M-Audio Revolution 5.1

Mouse- Logitech MX900

Case- Cooler Master Centurion 4

PSU- Antec True380 $61 Newegg <-might go with a bigger unit if I run multiple disks

So, o oracles of storage technology, which way should I go?

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I don't think anyone said RAID on the desktop was dumb. I agree that FC on the desktop sounds absurd.

RAID 0 is not redundant, so yeah, that's dumb. But other RAID levels do offer value on the desktop, especially RAID 1.

RAID 0+1 maybe has some value, but performance isn't part of it. It's probably faster than RAID 5 and useful for those needing to work with large files.

How are four 80gig drives in RAID0+1 likely to give you any improvement over two 160gig drives in RAID1? For that matter you could get two 250gig drives for less than four 80's, and now you don't need an expensive 4-channel RAID controller. Using only 160 gigs of a 250 gig volume will give you quicker seeks.

The bottom line is, what are you trying to accomplish? What are your goals with regards to performance, capacity, and redundancy?

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I don't think anyone said RAID on the desktop was dumb. I agree that FC on the desktop sounds absurd.

RAID 0 is not redundant, so yeah, that's dumb.  But other RAID levels do offer value on the desktop, especially RAID 1.

RAID 0+1 maybe has some value, but performance isn't part of it.  It's probably faster than RAID 5 and useful for those needing to work with large files.

How are four 80gig drives in RAID0+1 likely to give you any improvement over two 160gig drives in RAID1?  For that matter you could get two 250gig drives for less than four 80's, and now you don't need an expensive 4-channel RAID controller.  Using only 160 gigs of a 250 gig volume will give you quicker seeks.

The bottom line is, what are you trying to accomplish?  What are your goals with regards to performance, capacity, and redundancy?

Redundancy isn't a major issue, anything I really need to keep I put on my server, which runs U160 RAID5 and has a 7-slot SDLT library to back it up.

As for the RAID0+1 idea, that came from a friend of mine who works relatively high up in GM's IT department, as a consultant. He had said that as the number of spindles increases, so does throughput. Then again, I think he was speaking of high-end SAN implementations, not desktops.

Also, space isn't too much of a concern, even 70 minutes from 8 tracks of 24-bit/192KHz audio is only 36.8GB. I'm a 2K systems administrator by day, I know better than to keep my data on a desktop. I'd rather be able to run tons of disk-intensive software at once rather than have 2TB of storage on a desktop. I honestly don't know what I'd do with all that space, even if I got an HDTV tuner and started recording all my favorite shows uncompressed.

Lastly, a lot of the on-board SATA RAID controllers are coming with 4 ports now. I had originally looked at getting a 3Ware 8006-2LP controller and throwing it in a 64-bit PCI slot, but I looked at some side-by-side comparisons with the ICH6R, and they were pretty close. I'm not sure, but I believe the ICH6R uses the PCI Express bus, which would explain that.

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I think you'll get the biggest bang for your buck with a pair of non-RAIDed Raptors. Make one your system/swap drive and the other your data drive. Back up your system to the network on a regular basis. ;)

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I would not encourage the use of RAID 1. It can give a false sense of security. The problem with it is that, more or less instantly, the RAID 1 setup will have any problem that the primary boot drive has if it is a problem with data corruption, a virus, or an OS problem. That really is not a useful backup. All it gives useful protection against is physical failure of the primary boot drive. There is a place for such things, such as mission critical servers where the down time to reload the server from a backup is not desired (usually there will be a much larger RAID 5 array involved in the primary boot drive in such a circumstance though). It is not a substitute for an actual backup though.

The same applies to RAID 0+1 setups.

I would think that a separate drive which is used to keep an up to date backup would be more useful in a desktop environment.

RAID 0 can be pretty risky all by itself...a problem with either drive and all is lost.

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I would not encourage the use of RAID 1.  It can give a false sense of security.  The problem with it is that, more or less instantly, the RAID 1 setup will have any problem that the primary boot drive has if it is a problem with data corruption, a virus, or an OS problem.  That really is not a useful backup.  All it gives useful protection against is physical failure of the primary boot drive.  There is a place for such things, such as mission critical servers where the down time to reload the server from a backup is not desired (usually there will be a much larger RAID 5 array involved in the primary boot drive in such a circumstance though).  It is not a substitute for an actual backup though.

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The same applies to any RAID level with the exception of RAID 2. It protects against a single disk failure and can also provide protection from a single controller failure in SCSI and FC scenarios. It is not a backup - but it can and does enhance performance and protects against a type mechancial system failure, by far the most common type.

And frankly, if you're booting off a RAID 5 array, you need to hae your head examined. There is no good reason to boot off of a RAID 5 array - the performance to run the OS off of it is pretty horrible, even if all it is is a file server. Booting off of a RAID 1 array is much preferable, and then using additional arrays for additional storage if needed.

I would think that a separate drive which is used to keep an up to date backup would be more useful in a desktop environment.

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Fine, but he has that already. Remember that massive amount of network stoarge? And the SDLT? Sounds an aweful lot like my array + DDS4.

And for some more background information, the ICH5R is not a PCI-E device but uses a single proprietaty IHA 1.5 connection at 266 MB/s to the northbridge, shared with the PCI bus, all of the ATA channels, onboard sound and the onboard 10/100 NIC if it's there. Similarily, a PRO/1000CT network connection also has its own dedicated connection to the northbridge at 266 MB/s.

My suggestion would be to use two Raptors in RAID 1 for your OS, programs, swap and et cetera, and one large 7200 RPM PATA drives either independently or in RAID 1 for addational space. Audio files aren't particularily bandwidth intensieve, but the seek time on yoru OS and applications drive as well as having a seperate spindle for your data will help performance. FYI: CompUSA has 400 GB 7200.8 PATA's on sale for a few days for $200 after MIR.

Also, there's nothing wrong with FC on the desktop, but the drives you're talking about are fairly old to being with and will not outperform a Raptor, plus you'll be dealing with a single FC link at 2 Gbps full duples for all of the drives - somewhat less than the 100-150 MB/s per drive offered by ATA.

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