Slashdot Mirror

← Back to Stories (view on slashdot.org)

Hard Drives Made for RAID Use

Posted by CowboyNeal on from the little-spinny-different dept.

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."

51 of 201 comments (clear)

  1. Slashdot: Stories Made For Ad Use by Anonymous Coward · · Score: 5, Insightful

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

    1. Re:Slashdot: Stories Made For Ad Use by andrewman327 · · Score: 2, Interesting

      Does anyone have any benchmarks to back up this claim? This seems very vague.

      --
      Information wants a fueled airplane waiting at the hangar and no one gets hurt.
    2. Re:Slashdot: Stories Made For Ad Use by fimbulvetr · · Score: 4, Interesting

      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)?

    3. Re:Slashdot: Stories Made For Ad Use by ptbarnett · · Score: 4, Informative
      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

    4. Re:Slashdot: Stories Made For Ad Use by cperciva · · Score: 5, Informative

      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.

      --
      Tarsnap: Online backups for the truly paranoid
    5. Re:Slashdot: Stories Made For Ad Use by Rasta+Prefect · · Score: 5, Informative
      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.

      --
      Why?
    6. Re:Slashdot: Stories Made For Ad Use by tomhudson · · Score: 2, Interesting
      Theoretically, any cheap drive used in a raid will experience less wear per gig of RAID data storage, since it is only storing a portion of the data. It's a cheat. Also, MTBF is a theoretical extrapolation from failure time of individual components. In the hard disk industry, its relation to reality is about the same as Harry Potters'. But we should be used to that, just like a megabyte ain't a megabyte when they calculate capacities.

      Its like this quote from the article:

      In (sic) 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."
      It's all bullshit. Sure, it might be better than another drive for use in a raid, but its not like people couldn't consider IDE drives in the past, and that this is some miracle cure.

      Just look at what RAID means - Redundant Array of Inexpensive Disks. Lots of people use cheapie IDE hard disks in RAID setups. We've got a 4-drive terrabyte raid. Why would we consider expensive drives when the whole idea is to use cheap drives in a redundant array?

      Fuck the marketing departments. And fuck the PHBs who make their buying decisions based on them. Oh, right, the PHBs *ARE* getting fucked by the marketing departments. Sorry lads, carry on.

    7. Re:Slashdot: Stories Made For Ad Use by whoever57 · · Score: 5, Interesting
      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.

      --
      The real "Libtards" are the Libertarians!
  2. This is ridiculous! by Cerdic · · Score: 4, Funny

    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.

    --
    Advice for my fellow geeks: before seeking out that threesome you dream of, you might see what a TWOsome is like first.
  3. No NCQ? by gbjbaanb · · Score: 4, Insightful

    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?

    1. Re:No NCQ? by rsborg · · Score: 2, Informative
      Is this just marketing speak, has it truly included scsi features, or could it actually be better performing than SCSI in a RAID array?

      In snort, without NCQ, SATA drives are going to be slower than SCSI. The other two features probably just offset/mitigate the speed differences, but I would probably hold out for something that has NCQ (or just go SCSI) if I were building a RAID today.

      --
      Make sure everyone's vote counts: Verified Voting
    2. Re:No NCQ? by keltor · · Score: 2, Insightful

      I think that all SCSI RAID controllers disable it on the drives as the controller takes care of all queueing. Remember most of the SATA drives now have NCQ. WD chose to specifically disable this as their regular Caviar SE drives have queueing.

  4. Typo! by Anonymous Coward · · Score: 3, Informative

    "In works better in RAID..."

    You should change "In" to "It"

    Thank you very much.

    1. Re:Typo! by Anonymous Coward · · Score: 2, Funny

      It works better it RAID... No, that doesn't work either.

    2. Re:Typo! by Basje · · Score: 3, Funny

      You case insensitive clod!

      --
      the pun is mightier than the sword
  5. About time by Tuor · · Score: 5, Interesting

    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.

    --
    I love my computer -- You make me feel alright (Bad Religion)
    1. Re:About time by $RANDOMLUSER · · Score: 2, Interesting
      > ...especially for controllers since each channel is dedicated...

      I generally tend to agree with that, but as a guy running 8 200GB SATA drives on four controllers, I can tell you that the PCI bus gets saturated _way_ too quickly for my tastes.

      --
      No folly is more costly than the folly of intolerant idealism. - Winston Churchill
    2. Re:About time by Glonoinha · · Score: 2, Informative

      RTFA - they used a different type of encoding on these drives in order to implement the 'time-limited error recovery.' The problem is that the encoding is done on three-vector bi-furate substrate instead of the two-vector bi-furate substrate used in the Raptors, and the 3V stuff can't handle speeds of the 10k RPM (the lateral acceleration at 10k RPM is significantly more than at 7,200 RPM, and the 3V stuff is taller than the 2V stuff - hence the problem.)

      --
      Glonoinha the MebiByte Slayer
    3. Re:About time by Ilgaz · · Score: 3, Informative

      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 ;)

    4. Re:About time by sumdumass · · Score: 2, Informative

      8 drive on four controlers.

      You could get around that if you were to use a Adaptec Serial ATA RAID 2810SA with 8 ports or a more expensive Adaptec Serial ATA RAID 21610SA with 16 ports.

      You might look at the price and say too expensive but the speed and availible configuration should make up for it. Besides i got might for around $425 wich is less then thier suggested price. Also both these cards can use the waisted space from mismatched drive sizes as well run multiple raid volumes one each drive. What i like the most is the hotswap and hotspare were you could just leave a blank drive in and if one other drive failes it automaticaly recovers with the spare and you can replace the bad drive without rebooting. Another thing i like about the card is that it is a full controler and not one of these host based things. Your computer will just see it as a harddrive(s) without any special drivers. You can even access them from DOS, most linux kernels, as well as windows 95 and 3.11 (note the drives had to be small for 3.1 and 95 to see correctly).

      BTW, i don't work for adaptec or sell thier stuff. I'm just impressed with a product that finaly took alot of frustration away that has been associated with cheaper IDE and SATA ad-on cards. I'm sure there are better solutions availible. this is just one that i have found. Most of the cheaper (under $100) IDE,SATA,or raid controlers i have found use the system for thier existance. This is why you need a special driver in windows or linux to use it corectly. the extra cominucations here could be somethign saturating you pci bus (or helping it saturate)

    5. Re:About time by Fweeky · · Score: 2, Interesting

      Quite. 32bit 33MHz PCI (especially shared among on-board stuff *and* multiple card slots) is amazingly feeble these days, so consumer-level PCI Express comes not a minute too soon. Of course if you can afford and appreciate 8 200G drives you can probably also afford and appreciate a half-decent workstation/server board with PCI-X, but even a pair of modern drives can completely saturate the bus, and if you're into file sharing over GigE even one drive is way too much.

      For that matter even sharing /dev/zero over GigE on PCI is.. disappointing.

  6. How does a lack of NCQ help? by Nom+du+Keyboard · · Score: 4, Insightful

    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.

    --
    "It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
  7. SATA version may be new, but features are not new by ptbarnett · · Score: 4, Informative
    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.

  8. TechReport by JohnnyBigodes · · Score: 4, Informative

    Proper TechReport's review here.

    Go read. Now!

  9. native command queueing by garat · · Score: 4, Interesting

    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?

    --
    Support alternatives to Paypal: http://www.e-gold.com
  10. Sal Cangeloso is a moron by laing · · Score: 5, Insightful

    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.

    1. Re:Sal Cangeloso is a moron by TheOrquithVagrant · · Score: 2, Interesting

      What part of "don't care about data loss" did you fail to understand?
      Why would I want to waste %25 of my volume's storage capacity to get better data security on something where I don't _care_ about data security? And no - raid-5 doesn't match raid-0 for speed even on reads, at least not in my linux software raid setup. No "probably" about it - I have a raid5 volume running on the same hd's, where I keep data I actually care about.

    2. Re:Sal Cangeloso is a moron by GungaDan · · Score: 2, Informative

      Not to niggle, but your assessment is incorrect. RAID-0 is equally as redundant as RAID-1. There are two disks performing a job that either one of them could do alone. The second disk is redundant. RAID-0 uses the redundancy for performance instead of continuous backup.

      OK, so it was just to niggle.

      --
      Eloi are stupid, throw morlocks at them!
  11. NCQ.. by groovy.ambuj · · Score: 2, Informative

    NCQ allows hard drive to reorder various commands/accesses to suit its current head position. Depending on your app you might not see a lot benfits from it e.g when you do serial access all the time but lack of it will certainly cause degradations when multiple apps are active. Also by using one big hard-drive instead of multiple smaller ones its putting all eggs in one basket. Mechanical problems are more frequent than magnetic ones for a hard drive..

    --
    This sig doesnt exist.
  12. looking for an inexpensive raid5 tower by v1 · · Score: 4, Interesting

    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?)

    --
    I work for the Department of Redundancy Department.
    1. Re:looking for an inexpensive raid5 tower by John+Napkintosh · · Score: 2, Insightful

      Seems like you could save quite a bit of money by going with something like this (assuming it was SATA you're looking for):

      http://www.macgurus.com/productpages/sata/satakits .php

      They have 2-, 3-, 4-, and 8-bay kits to suite your need. Get 'em with or without drives, cables, etc. The only drawback I see is the lack of a controller card (might have to go with something like the Sonnet further down the page). Then again, this may not be such of a drawback, since you're not stuck with a built-in RAID controller, in the event of it being a pile of junk.

      $451 for an empty 8-bay with no cabling ain't too bad.

      --

      Long signatures suck.
  13. Network RAID? by Eccles · · Score: 4, Interesting

    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?

    --
    Ooh, a sarcasm detector. Oh, that's a real useful invention.
    1. Re:Network RAID? by canadiangoose · · Score: 2, Informative
      I really think your best bet would be to use an old P3 or Athlom running software RAID on Linux or BSD. You can add several PATA/SATA cards to your machine and stack it full of drives and fans, and I think you'll find the performace to be acceptable. Of course, no software RAID can compete with an expensive SCSI RAID card with a dedicated XScale chip or whatever, but it's a heck of a lot cheaper.

      It also depends what you want to be doing with it. I've played with both hardware and software RAID5 and home and at work. Software RAID offers excellend bandwidth, and seems to use very little CPU time. This is why I think a P3 should work. However, the seek time is terrible. Perhapse it has something to do with the RAID intelligence being located so much farther away from the drives than it would be with a dedicated RAID card. I've tried running an SQL server on soft IDE RAID on a dual Xeon 3.2, and it had the snot kicked out of it by a dual P3 700 with an ancient MegaRAID driven SCSI array.

      As for running it as a home directory for Win/Mac/Linux, between Samba and NFS you should be just fine. You may even be able to go the fancy route and set up a few logical volumes as iSCSI targets and run your own SAN.

      --
      Never eat more than you can lift -- Miss Piggy
    2. Re:Network RAID? by xlsior · · Score: 2, Informative

      One of the major reasons for the high price of most hardware RAID5 solutions, is the hot-swap backplane. If you are OK with a solution where you would have to shut down the server in order to replace a bad drive (which would be OK for most home use I would image), you can find some *very* cheap hardware RAID controllers ($50, for both ATA and SATA) that will do the job just fine...

  14. Dumb Drives by Doc+Ruby · · Score: 2, Interesting

    EIDE drives are the cheapest type. But AFAIK, each drive has a controller card onboard, which seems redundant when all the drives are being controlled in conjunction. Software RAIDs seem to have parity (pun intended ;) with HW raid controllers, but wouldn't a real "Made for RAID" drive have nearly no controller logic of its own (maybe just data separator and head/spindle speed/position calibration)? Lots of logic for controlling the RAID drive will be on the central controller card, or running on the CPU. So why have more on the drive? The cheaper the drives, the bigger the array at the same budget (shared overhead of common controller).

    Am I correct, or are some RAID drive makers already doing this? Or have I just got all the controller:drive economics wrong?

    --

    --
    make install -not war

  15. Is it just me or.... by rongage · · Score: 4, Insightful

    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.

    --
    Ron Gage - Westland, MI
  16. Re:How about RAID on a hard drive itself by LuckyStarr · · Score: 2, Insightful

    And what if the electronics of the drive fails? Or the motor? Or the drive-head actuator?

    Sorry sir, but this is a bad idea.

    --
    Meme of the day: I browse "Disable Sigs: Checked". So should you.
  17. Buffalo TeraStation by chocolatetrumpet · · Score: 4, Informative

    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.

    --
    Spoon not. Fork, or fork not. There is no spoon.
  18. Re:earth to 11 year old kid by alc6379 · · Score: 5, Interesting
    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.

    --
    I don't moderate anymore. Karma penalty for 90% fair mods? Can I mod that unfair?
  19. What would REALLY make the drive RAID firendly by jandrese · · Score: 3, Insightful

    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.

    --

    I read the internet for the articles.
    1. Re:What would REALLY make the drive RAID firendly by swmccracken · · Score: 2, Interesting

      Recent promise RAID cards have a "gigabyte boundrary" mode, where they round the size of the array down to the nearest whole gigabyte.

      This allows for minor variations in replacement disc sizes, at the cost of wasting some disc space. (It'd make a 250 gb array instead of a 250.23 GB one.)

  20. synchronized spindles? by adrianmonk · · Score: 3, Informative

    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.

  21. Western Digital is synonymous for crap by Rev.LoveJoy · · Score: 2, Insightful
    In my whole IT career (some ... christ ... 13 years now) I have seen no other vendor of HDD that comes close to WD for sheer volume of failed drives (Maxtor is a distant 2nd). That they resort to cheap marketing gimmicks like this (1 million hours mean time between failure, puhleeze, these are the people who pioneered the 1 year warranty) is only so much more indication of their propensity to manufacture garbage.

    Buy their gear if you must but I would not put my data on it.

    -- RLJ

    1. Re:Western Digital is synonymous for crap by rizzo320 · · Score: 3, Interesting

      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!

    2. Re:Western Digital is synonymous for crap by dtfinch · · Score: 2, Interesting

      I personally trust WD more than I trust Maxtor, but all manufacturers have bad years and bad models. This year I only trust Seagate, on only certain specific models.

  22. 3 platters by dtfinch · · Score: 2, Insightful

    I'm no expert, but I look forward to mostly buying 2 platter drives from now on. Early failures seem to double when you add a third platter, and 5 platters is just scary. You can get 250gb SATA 2 platter Seagate drives for about $110 each, which seem to have a great record for reliability so far. But when I need real SCSI reliability I'll just get a real SCSI. The warranty for most SATA drives may be 5 years, but usually it's void if you put it in a server.

  23. Re: Go RAID! How real? by MarkTina · · Score: 2, Interesting

    What do you mean sat on the wayside ? It's been out and about for donkeys years, I've been involved in storage for 9 years and it pre-dates me by a LOOOONG time.

  24. Re:How about RAID on a hard drive itself by Pop69 · · Score: 2, Insightful

    Did you miss the Redundant bit in Redundant Array of Inexpensive Disks ?

    The idea is that one drive going bad doesn't take out the whole array in mirror, not that you have it all on one drive you fool.

  25. Re:SATA version may be new, but features are not n by Mechcozmo · · Score: 2, Funny
    I bought one to replace what I thought was a bad drive in a RAID configuration about a year ago.

    "Yeah, boss... drive, uh, died. I'll get a nice new one-- let me... uh... take this one home. I think it's, y'know, dead. Honestly this time."

  26. Not slower than SCSI by Jamesday · · Score: 2, Informative

    Since I wanted some facts, Wikipedia ordered two systems for database service, both dual Opterons with 4GB of RAM and six drives. One with 10,000 RPM SCSI drives and one with 10,000 RMP SATA drives. The SATA system, without NCQ, was generally faster and ended up with a higher proportion of the site load assigned to it. The SCSI system was sometimes faster in mixtures which included lots of writes with lots of reads and that made it lag a bit less in replication of bulk update operations, so newer systems have been SCSI. If more drive bays had been available, adding another couple of SATA drives would probably have made the SATA set faster for that case as well and still cheaper.

    If lower access times are needed, SCSI drives beat SATA drives just because you can only get 15,000 RPM with a SCSI interface. May also make sense to have 15,000 RPM drives if you're already spending a lot of money on 16GB of RAM.

    The question about this drive which interests me is whether drive write caching can be easily turned off and will stay off, so you don't lose database data when the database thinks the data has been flushed to the surface but it hasn't really been flushed. If you can't do that, it's unsuitable for a lot of database work - certainly unsuitable for use with RADI controllers with battery backed up write caches, where you have the battery to make sure you don't lose cached data if the power goes off. Anyone who things colo power and UPS will protect against loss of power hasn't suffered enough yet... :)

  27. RAID 0 is fine, in its place by Jamesday · · Score: 2, Informative

    So, I have seven database servers, all with identical copies of the data. Do I really care if I lose all the data on one of them because one drive in a RAID 0 set fails? The completely redundant systems do the job better than any RAID setup can.

    You consider RAID 0 when you don't care about losing the data if there's a drive failure and want the benefits of striping and the extra space available for a given number of drive bays, compared to other RAID levels. RAID 5 can get you some of the space but it's slower for database work.