Hard Drives Made for RAID Use

An anonymous reader writes "Hard drive giant Western Digital recently released a very interesting product, hard drives designed to work in a RAID. The Caviar RE SATA 320 GB is an enterprise level drive without native command queueing and uses an SATA interface. In works better in RAID than other drives because of features like its time-limited error recovery and 32-bit CRC error checking, so it is an option when previously only SCSI drives would be considered."

Comments

Slashdot: Stories Made For Ad Use

[Anonymous Coward]

Sheesh, this is a VERY thinly disguised ad. Here's a direct link to NewEgg $169. Has the same details as this "story."

Re:Slashdot: Stories Made For Ad Use

[fimbulvetr]

On the newegg link they list the MTBF as 1 million hours. Google tells me that that is about 114 years. How can it have such high mtbf? Is that newegg just not having correct data or is there something special about these drives (or are they designed to be "used" less)?

Re:Slashdot: Stories Made For Ad Use

[ptbarnett]

Is that newegg just not having correct data or is there something special about these drives (or are they designed to be "used" less)?

It's not an error by NewEgg. Follow the link to the manufacturer's site, and you'll see the same specification:

http://www.wdc.com/en/products/Products.asp?DriveI D=114

Re:Slashdot: Stories Made For Ad Use

[cperciva]

On the newegg link they list the MTBF as 1 million hours. Google tells me that that is about 114 years. How can it have such high mtbf?

MTBF is defined as [short time period] * [number of drives tested] / [number of drives which failed within that time period]. An MTBF of 114 years doesn't mean that half of the drives will survive for 114 years without a failure; it means that if you run 114 drives for a year, you should expect to have 1 failure.

A more intuitive way of conveying the same information is to say that the drives have an expected failure rate of no more than 1E-6 per hour.

Re:Slashdot: Stories Made For Ad Use

[Rasta Prefect]

On the newegg link they list the MTBF as 1 million hours. Google tells me that that is about 114 years. How can it have such high mtbf? Is that newegg just not having correct data or is there something special about these drives (or are they designed to be "used" less)?

Easy: You, like most people, don't know what MTBF means. MTBF is only meaningful in context with the expected lifespan of the device. This is probably somewhere in the neighborhood of 5 years, or about 43,800 hours. Essentially, what the manufacturer is saying is "Based on some data, we estimate that if you run x number of these drives, the average time between failures will be 1,000,000/x hours, up until the expected lifespan of the drive, at which point all bets are off"

For computer hardware this is always some sort of extrapolated estimate, since they have of course not actually been testing the drive for it's expected lifespan, or it would be obsolete by the time they released it.

Re:Slashdot: Stories Made For Ad Use

[whoever57]

An MTBF of 114 years doesn't mean that half of the drives will survive for 114 years without a failure; it means that if you run 114 drives for a year, you should expect to have 1 failure.

That is a good explanation. Many people confuse MTBF with lifetime.

Most products (and especially electronics) have a failure rate that when plotted over time looks like a bathtub. There is a high initial failure rate (infant mortality) that drops over time to a base rate (the random failure rate described by MTBF), this low failure rate continues until one reaches the end of useful life of the product, when the failure rate rises once again as age and wear effects cause the device to fail.

Note that most extended warranties are designed by the seller to kick in after the early failure rate has droped, but expire before the end-of-life failures.

This is ridiculous!

[Cerdic]

If they would stop eating around the hard drives, leaving crumbs in them, we wouldn't need to use Raid to take care of the cockroaches in them. Ugh.

No NCQ?

[gbjbaanb]

Interesting that they don't have NCQ, whereas SCSI drives generally do (well, called TCQ on SCSI IIRC)

Is this just marketing speak, has it truly included scsi features, or could it actually be better performing than SCSI in a RAID array?

Typo!

[Anonymous Coward]

"In works better in RAID..."

You should change "In" to "It"

Thank you very much.

Re:Typo!

[Basje]

You case insensitive clod!

About time

[Tuor]

While I've been a proponent of SCSI for a long time -- Apple really was thinking ahead when it had it in Macs all those years -- it has been getting thread-worn. Ultra-wide-tall-double-hex-SCSI is just getting to be too much!

SATA is the right technology, especially for controllers since each channel is dedicated. The only alternative is Firewire, and there are no native controller drives.

Re:About time

[Ilgaz]

Well, serial attached scsi started to ship

http://www.adaptec.com/sas/index.html?source=home_ story1a_SAS_technology_home

Pro level already moving but I suspect it will be OK for home with enterprise features it offers.

I checked a bit you know ;)

How does a lack of NCQ help?

[Nom du Keyboard]

How does the lack of Native Command Queuing improve RAID performance? Generally I thought NCQ improved all drive's performance, and TFA says that NCQ is normally part of Enterprise High-Performance.

SATA version may be new, but features are not new

[ptbarnett]

Western Digital has been selling an EIDE version with this feature set for a while:

http://www.wdc.com/en/products/Products.asp?DriveI D=92

I bought one to replace what I thought was a bad drive in a RAID configuration about a year ago.

TechReport

[JohnnyBigodes]

Proper TechReport's review here.

Go read. Now!

native command queueing

[garat]

Here's an interesting quote from Tom's Hardware:

"In sum, we must state that all Command Queuing enabled drives have an advantage over those that do not support this feature. At the same time, CPU load is also slightly higher when Command Queuing technologies are used. However, considering the performance of today's processors, the additional CPU load is a marginal factor."

Basically, you put some load on the processor for increased disk performance... Why not include it?

Sal Cangeloso is a moron

[laing]

The manufacturer specifically says to only use these in a RAID-1 configuration (mirroring). They have a reason for this: The error recovery mechanisim is abbreviated. So what does Sal do... He connects two drives in a RAID-0 configuration. Now his data reliability has gone to about 1/4 of a regular drive.

looking for an inexpensive raid5 tower

[v1]

These buggers are hard to find for anywhere near decent cash. I've found one model that is fairly popular, going by several different names and brands, but nobody seems to have them in stock. They look like a GREAT deal and loaded with most or alll of the best features of raid5. (hot swap, live rebuild, live GROW, etc) Has anyone seen one IN STOCK anywhere?

Same exact models:

http://www.raidweb.com/fb605fw.html
http://www.micronet.com/General/prodList.asp?CatID =45&Cat=Product
http://www.firewiremax.com/fire-wire-1394-ilink/mi harasyfor5.html
http://www.pcrush.com/prodspec.asp?ln=1&itemno=779 19&refid=1057
http://www.cooldrives.com/firewire-raid-5-enclosur e-mini.html
http://www.topmicrousa.com/combo-205.html

same internals, different enclosure:

http://fwdepot.com/thestore/product_info.php/produ cts_id/657
http://www.cooldrives.com/fii13toatade.html

Everyone I call says they have them in stock. Then I ask them to check and they suddenly change their mind and say no it's not really in stock, (despite what their web page says) and they expect it in the generic "1-2 weeks". (retail-speak for "we don't know when it'll be in, please call back later")

Two of them actually told me they have yet to receive any of these units, so I don't think they've shipped from the manufacturer yet? (vaporware?)

Network RAID?

[Eccles]

Is there a reasonable cost, relatively low power RAID-5 setup for home networks? I'd love to set up a file server with gigabit ethernet and RAID-5 to serve as the home directories for my multiple machines. Things like the Buffalo LinkStation are a step in the right direction, but no RAID, etc. Is my only solution a Celeron or Pentium-M based PC? If so, is it possible to set up such a system to act as home directories for a combo of Windows, Mac, and /or Linux machines?

Is it just me or....

[rongage]

Is it just me, or did this review stink for lack of proper testing and comparison...

If I were comparing this product and it's performance, I certainly would not be benchmarking a SATA based RAID setup against a single Parallel ATA drive. Something in this arrangement just doesn't seem... well, logical.

If you were really going to try to impress me with it's performance, then you would have to show me how it compares to "non-RAID" optimized drives of near simular characteristics. Show me how this drive performs against, say, Hitachi SATA 320 gig drives using an identical test rig. Also show me how this drive compares to 320 gig SCSI drives. Show me the results as JBOD, RAID-0, RAID-1 and RAID-5. You know, like the real world.

While the graphs are pretty, I'm afraid that this "review" it fairly content-free.

Buffalo TeraStation

[chocolatetrumpet]

Buffalo TeraStation

Supports RAID 5.

I emailed if external USB hard drives could be added and swapped to a raid 5 array, and if it can be done "on the fly"...

but all I got was this lousy message:

"Please call (800) 456-9799 x. 2013 between 8:30 and 5:30 CT and our presales guys will be able to assist you."

I'm one of those weird people that would rather communicate in writing. Oh well - no sale.

Re:earth to 11 year old kid

[alc6379]

Mod me offtopic, or whatever, but this has to be the most dumb-ass review I've ever read. It's a drive meant for RAID use, as in RAID 5 or RAID 1, in servers, where data integrity is very important. But what does this guy do?

...he puts it through the paces of a desktop hard drive. Where's the test of how it could run under mySQL? It's been replaced by a comment about how you can never have too much space "in this age of DVD-burning, file-sharing, and 40 GB MP3 players." Who the fuck cares about that on a server?

Where's the review of how well it facilitates serving pages through Apache? Oh, that's replaced by "Look how neat the drive looks!"

...Nope. This FA was a waste of time, not just for the reader, but for the author, and for Western Digital to have even sent the drives to this guy. He should go back to playing UT2k4OMFGBF2, and find someone who actually knows something about industry usage patterns on hard drives like this to write a thoughful review.

What would REALLY make the drive RAID firendly

[jandrese]

IMHO, the biggest things manufacturers could do to make the drives more RAID friendly is to change the name (even with just a v1, v2, etc...) when they change platters.

Nothing is worse than buying a bunch of drives and a couple of spares and building the array and then discovering down the road that in fact one of your spares came from a different production run and has a slightly different (maybe 3 block smaller) geometry and can't be used on your array. Usually there is absolutely no indication on the box or the drive that one of your drives is different unless you decode the cryptic serial number.

For that matter, just printing the exact LBA count on the back of the box would be a huge boon.

This isn't limited to ATA drives either. I've seen it plenty of times in professional SCSI solutions too, especially as the arrays start to get older.

synchronized spindles?

[adrianmonk]

I would think if these drives are really designed for RAID (like other drives have been in the past), then they would have support for synchronized spindles.

The idea behind synchronized spindles is that in order to read data from a disk, you have to wait for the platter to come around part of a revolution for your data to become available, just like picking up your suitcase on the luggage carousel at the airport. How long you need to wait is a matter of luck, because the disk can be assumed to be in a random position when you decide you want your data. When you have RAID without synchronized spindles and you want data that's bigger than the stripe width (or when you're writing and need to update the parity), you have to wait for multiple disks, and they will tend to be spread out so that you tend to wait longer than if you were just waiting for one. With synchronized spindles, as soon as the whole group hits the right position, you've got what you're looking for, and you're done.

So, the point is, not having synchronized spindles tends to increase average access time, so having synchronized spindles is a desirable feature for a drive designed specifically for RAID.

Re:Western Digital is synonymous for crap

[rizzo320]

Wow, did Western Digital plot to have your family killed? What a vendetta!

All hard drive manufacturers have gone through cycles of poor quality and reliability. Maxtor, Seagate, IBM/Hitatchi (remember the "DeathStar") have all had the same problems. In all my years of repairing and building desktops, I can say I have had the most problems with Seagates and (the now owned by Maxtor) Quantum drives. If you ask someone else, they'll give you a different answer too.

This drive has a 5 year warranty. Most other Western Digital's have a 3 year warranty, even if you buy the OEMs (in most cases). And read the articles above for what 1 million hrs MTBF means!