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Seagate Cheetah 15K.6

SAS Storage: High-Performance Hard Drives
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Seagate has always been serious about its Cheetah drive, which represents one of the finest enterprise hard drive families in the industry. We received the latest generation, the Cheetah 15K.6. This is still a 3.5” hard drive, utilizing a SAS/300 or Fibre Channel interface, featuring 16 MB of cache and spinning at a fast 15,000 RPM. While none of this sounds spectacular, the new drive introduces a number of improvements over its predecessors.

Up to 450 GB Capacity

The most obvious improvement is the capacity bump, which was really overdue in light of 1 TB capacities having been available in the desktop space for more than a year, and notebook drives reaching 500 GB. Seagate offers Cheetah 15K.6 drives at 450 GB, 300 GB and 146 GB (4, 3 and 2 discs). The higher capacities were made possible by—you guessed it—perpendicular recording technology, which finally is making an impact in the enterprise space as well.

1.6 Million Hours MTBF

Seagate’s data sheet emphasizes reliability, with a 1.6 million hour mean time between failure figure (0.55% annual failure rate stated), and a 5-year warranty. This, however, isn’t a big deal, as all enterprise-class products are typically covered for five years.

Impressive Performance

While Seagate talks about a maximum sustained transfer rate of 164 MB/s, we actually measured as much as 174.6 MB/s maximum read throughput, and about the same number for writes. Minimum throughput always stays above 100 MB/s, which clearly is a new record for mechanical drives, and equals almost a 40% improvement over the predecessor Cheetah 15K.5 or other 15,000 RPM units. This is actually even more impressive than the maximum throughput.

The average access time of 5.7 ms cannot match the 0.5 ms or less we find with flash SSDs, but this drive still delivers best-of-class access times. In fact, it’s interesting to see that the Cheetah 15K.6 is actually head to head with the 2.5” Savvio 15K.1, which has been the fastest in access time so far.

Disk Encryption as an Option

Seagate offers a full disk encryption (FDE) version of this drive, but it is not going to be available at retail. Instead, Seagate ships these only to some large OEMs. The manufacturer makes some good points about the FDE feature on the data sheet, as it does have more advantages than just plain security, by encrypting files on the fly. For example, drive decommissioning cost can be neglected for FDE drives, as you do not have to carefully erase existing data.

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  • -3 Hide
    tai_anjing_lu , August 26, 2008 8:00 AM
    Expensive price for such capacity. I prefer buying 2 x 500 GB or a terabyte for larger capacity.
  • 0 Hide
    somasaint , August 26, 2008 9:18 AM
    1x OCZ 64GB SATAII SSD = ~270$USD [pricewatch]

    or

    2x 15k_rpm Fujitsu SAS 73GB + Dell PERC 5i = ~200$USD [ebay]

    superior initial performance and incredible scalability and RAID options.

    the choice is obvious..
  • -3 Hide
    neiroatopelcc , August 26, 2008 9:20 AM
    This looks awesome! I wonder if one of those could replace my 3x WD Raptor 36 (striped) ; sas drives don't work on an ordinary ich9r controller do they?
  • -1 Hide
    somasaint , August 26, 2008 9:41 AM
    neiroatopelcc,

    sorry.. SAS requires an aggressive commitment. typically SAS
    controllers cards come in pci-x, but the dell perc 5i line can
    be found [ebay] in the pci-e version.. given your mainboard has
    a free pci-e 8x slot .. which usually means an SLI board.. or triple
    for those of you already running twin rigs. the benefits here being
    you can set your stripe size to 1mb.. and you get ddr256mb cache + BBU.

    here are my figures: via HDTach [raid-0: 73GB 15k sas fujitus + perc5i]
    http://img403.imageshack.us/img403/940/boredeq1.jpg
  • 0 Hide
    Turas , August 26, 2008 10:01 AM
    How about some sound tests? I have been debating these versus SSD since they were announced but was curious as to just how loud they were. You do mention you can easily hear it but it would be nice to get a sound reading from say 1 meter away or somethign like that. Also how hot are the drives getting? How much cooling will I need for these, especially with 3 or them in the box?

  • 0 Hide
    dangerous_23 , August 26, 2008 10:05 AM
    which would be better for a thin client server, SSDs or one of these SAS drives?
  • 1 Hide
    ceteras , August 26, 2008 10:38 AM
    http://www.vr-zone.com/articles/ASUS_Announced_P6T_Boards_For_Core_i7_Nehalem/5978.html

    ASUS Announced P6T Boards For Core i7 Nehalem

    SAS Support for Server-level Storage

    To match the supreme performance of the new platform, the ASUS P6T Deluxe will adopt the SAS (Serial Attached SCSI) controller to let users utilize SAS hard disks. These hard disks will provide higher data transmission speeds and better data storage reliability in comparison to current SATA interfaces; and could herald the start of a new standard for mainstream storage devices that caters to enterprise users. With this technological improvement, users will be able to connect 2 SAS hard disks to the P6T Deluxe without the need to purchase an extra SAS controller card. Performance-wise, an SAS hard disk gains a 39% improvement on PC Mark HDD Test benchmarks when comparing RAID 0 performances with SATA (supported by SB ICH10R) interfaces.
  • 0 Hide
    neiroatopelcc , August 26, 2008 10:57 AM
    Ouch that dell controller is expensive on ebay.de - It'd be cheaper to buy a (new) promise controller for 2 sas drives and a riser adapter to utilize it in a pcie slot (got a p35 board with a x4 link in a physical x16 socket), and get a sas drive or two.... that or wait till nehalem and pray for some other vendor (gigabyte, msi or abit) to implement a sas controller too. No way in hell I'll buy another asus board if I'm given a choice.
  • 6 Hide
    Anonymous , August 26, 2008 11:07 AM
    It would be nice if the article could actually put SSD numbers in the charts since they keep making reference to them in the text. Just the top 2-3 SSDs would be good so we don't have to manually hunt down other articles to really make the comparison.
  • 0 Hide
    wtg , August 26, 2008 1:40 PM
    I think I'll buy 2 Cheetah's and put them in a Raid 0 for my new video workstation !!!
  • 0 Hide
    martin0642 , August 26, 2008 1:57 PM
    Access time alone makes SSDs a better option, that and the noise, MTBF and RAID scaling.

    I've heard the "Clunk of Death" from head platters for the last time.
  • 1 Hide
    Bait , August 26, 2008 1:59 PM
    Has anyone looked at Compact Flash Cards as an alternative to the $1000 32GB SSD's? 32GB Compact Flash Cards (~$100) are cheap in comparison.
  • 0 Hide
    nbk_redspy , August 26, 2008 2:37 PM
    I agree, I expected to see the SSD numbers as well, but from the last couple of SSD articles, Tom's seemed to be a little behind on the latest SSD models.

    For example, using the OCZ Core when the superior Core II was commercially available.
  • 0 Hide
    Mathos , August 26, 2008 3:32 PM
    martin0642Access time alone makes SSDs a better option, that and the noise, MTBF and RAID scaling.I've heard the "Clunk of Death" from head platters for the last time.


    Yes instead of MTBF you have time before cells start dieing out from too many read write cycles.

    Noise is good though, less power usage is good, and IO performance as far as access times are an advantage.

    But the trade off is storage cap, huge price per gig difference. And things like that. I think the best option would be to make a hybrid drive. Things that need high I/O access speed stay on the flash drive, things that need mass storage go on the mechanical disk.
  • 0 Hide
    Anonymous , August 26, 2008 3:46 PM
    don't forget Intel's upcoming SSD's! They're even faster, and ?cheaper? maybe as well.
  • 0 Hide
    Turas , August 26, 2008 5:19 PM
    nbk_redspyI agree, I expected to see the SSD numbers as well, but from the last couple of SSD articles, Tom's seemed to be a little behind on the latest SSD models. For example, using the OCZ Core when the superior Core II was commercially available.

    AS far as I know the Core II are not yet available.
  • 0 Hide
    yyrkoon , August 26, 2008 6:52 PM
    Well, you can get the Seagate ST3146356SS (147GB) version for around $285 usd before shipping. You can also buy a decent non RAID/PCIe controller(2 port as I recall) for around $80 usd. With shipping and all factored in, we're talking about roughly $400 usd for a single 147GB drive + controller.

    That is not too bad *if* you need to performance for video editing, or possibly image retouching(scratch disk) if you are a professional. You may even see a noticeable performance increase on a gaming rig, but really the cost/storage ratio really does not make sense for most. Also while you may have mentioned it, I did not see mention of it - SSDs having no moving parts, would not cause issues with performance because of vibration. Another thing is that *if* you stripe, access times may still nearly double(as compared to a single drive), but access times on SSDs being as small as they are . . . well, it would become a moot point.

    On the other hand, I have been thinking for a long time now that SAS HBA's in the home could make sense for the enthusiast. SAS HBA + decent SATA drives may not offer the same performance, but with the right card, and possibly SAS expanders, SAS + SATA == a solution that can scale over time, and can possibly offer performance greater than the home desktop could ever hope to keep up with. Cost effective SAS expanders however are hard to find(for said purpose), which could be the only caveat, other than having an external(*if* external) array that can not be hooked up to just any old system.

    Good to see that Seagate is still pushing that performance level higher with their Enterprise drives.
  • 2 Hide
    yyrkoon , August 26, 2008 7:05 PM
    somasaintneiroatopelcc, sorry.. SAS requires an aggressive commitment. typically SAScontrollers cards come in pci-x, but the dell perc 5i line canbe found [ebay] in the pci-e version.. given your mainboard hasa free pci-e 8x slot .. which usually means an SLI board.. or triplefor those of you already running twin rigs. the benefits here beingyou can set your stripe size to 1mb.. and you get ddr256mb cache + BBU.here are my figures: via HDTach [raid-0: 73GB 15k sas fujitus + perc5i]http://img403.imageshack.us/img403/940/boredeq1.jpg


    Dell is not the only company you can buy SAS HBAs from. Adaptec, LSI Logic, and 3Ware all sell SAS HBAs. As does Areca, and several others I do not care to think of at the moment. You can get them at anywhere from $80usd for a basic controller, on up into $1000's in the PCIe variants. PCI-X variants are mostly a bit cheaper than their PCIe counterparts, but that probably has to do with supply, and demand.

    The price point for a decent controller with 128 + device support through expanders starts at around $400-$450 usd. Expanders on the other hand will also set you back $300-$400 depending on where you get it from, and in what form. Expander racks are ridiculously priced . . .
  • 0 Hide
    kittle , August 26, 2008 10:20 PM
    Yes SAS is expensive - but you get what you pay for, namely high performance, and reliability. In the server market, when your data is worth large sums of money or downtime is expensive, then the higher price of these drives make perfect sense.

    The other thing that wasnt mentioned is heat. the 15krpm spindle speed produces quite a bit of heat, so the drive must be cooled, which means fans and still more noise, and so forth and so on...
  • -1 Hide
    nvalhalla , August 27, 2008 2:14 PM
    MathosYes instead of MTBF you have time before cells start dieing out from too many read write cycles.



    When HDD fail it's all at once. I'll take slow cell death over catastrophic failure any day.
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