Introduction

Storage sits at the heart of every system, from a notebook right up to a rack filled with servers. It wasn't long ago that a hard drive was a fairly expensive component that offered significantly less capacity than the massive drives available today. Today, the IT consumer has to decide between SATA/SAS/Fiber Channel, and sizes ranging from 36GB up to 750GB (SATA). But perhaps the most interesting transition that has occurred in the enterprise storage arena in the last few years is the impact that the desktop market has had on the direction of the enterprise storage market.

A few years ago, the enterprise storage market was SCSI or Fiber Channel. If you wanted a chassis full of drives in a DAS (direct attached storage) configuration or in a SAN (Storage Area Network), it came with SCSI or Fiber Channel drives. At the time drives started at 9GB and topped out at 74GB and connected to an Ultra160 SCSI interface, or possibly a 2Gbit Fiber interface. Below is an excellent image from IBM (courtesy of StorageReview), that details 15 years of history for the hard drive.


The evolution of today's IT storage

The desktop market has been driving storage higher and higher every year, which of course impacts the IT market, since IT has to back up those drives. Now the enterprise is full of SATA offerings for near-line storage, and even in some more expensive SAN products like EqualLogic. SATA offers decent performance for long term storage and even some small to medium sized back-end applications. However, it can't compete with the latest evolution in high-performance storage for the IT market, SAS (Serial Attached SCSI).

Serial Attached SCSI was introduced into the IT storage market in 2004, and has been growing exponentially every year. We are now at a point where Parallel SCSI is starting to fade very rapidly, with most new servers using SAS instead of Parallel SCSI. Even though there was a specification for Ultra640, most manufacturers skipped right over it and adopted SAS as the next SCSI evolution.

Basic SAS Architecture
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  • JarredWalton - Monday, February 5, 2007 - link

    "or seek times" = "where seek times"
  • yyrkoon - Saturday, February 3, 2007 - link

    many 'old timers' are going to claim SCSI is better than anything, because its been around a long time, and has a proven track record. What these 'old timers' don't realize, is that SAS, and SCSI drives, share the same ancestry, except that SAS, also shares a history with SATA. *shrug*
  • mino - Sunday, February 4, 2007 - link

    Yes they are those.
    However most posters here do NOT dispute the benefits and superiority os SAS over U320.
    The point is that according the numbers published even SATA 7.2k is on par with SCSI320 10k !!!
    Those numbers simply coudn't be much more away from the reality then they are.

    Artificially more than halving the performance of a tested platform simply is not acceptable.

    Also to make tables in the sense SATAI vs. SATAII vs. SCSI vs. SAS is on itself seriously misleading to the extent that best thing to do for AT (provided they were not paid for it!) would be to call in the article eithe indefinitelly or for rewrite.

    Actually the reality is:
    SATA I or SATA II driver do not exist, there are only SATA drives inn existence as of now.
    performance-wise on single to 6-drives/system:
    SATA(7.2k) < SATA(10k) < SCSI(10k) = SAS(10k) < SCSI(15k) = SAS(15k)
    on 8+drives system:
    SATA(7.2k) < SATA(10k) < SCSI(10k) < SAS(10k) < SCSI(15k) < SAS(15k)

    For an 12-drive test the results should be:
    SATA(7k) << SCSI(10k) << SAS(15k) which is obvious even before any testing.

    However much more beneficial test would be:
    SATA(10k-Raptor) vs. SCSI(10k) vs. SAS (10k) with SCSI and SAS driver ideally from the same line.
  • mino - Sunday, February 4, 2007 - link

    "SATA I or SATA II driver" --> "SATA I or SATA II drives"
  • mino - Saturday, February 3, 2007 - link

    Yes, one sometimes has to make compromises.
    But benchmarking SCSI setup with 12drives on a SINGLE cable is plain stupid and tabloid-like aproach.
    This organization seriously criples perfromance and is NEVER used unless there is some very serious reason for it.
  • mino - Saturday, February 3, 2007 - link

    If you did have no SCSI option than the one you used, you should not have published those "SCSI" numbers at all. Those numbers as they are have nothing to do with SCSI being poor, they are simply showcasing that 3yrs 10k drive are slower than new 15k drives. Nothing new here.
  • Googer - Friday, February 2, 2007 - link

    That chart is missing the old 5.25 inch drives. The most famous of those was probably the Quantum Bigfoot. Quantum was bought out by Maxtor.

    http://images.anandtech.com/reviews/it/2007/promis...">http://images.anandtech.com/reviews/it/.../promise...

    http://www.pcguide.com/ref/hdd/op/formIn525-c.html">http://www.pcguide.com/ref/hdd/op/formIn525-c.html
  • Justin Case - Friday, February 2, 2007 - link

    Maybe the article author should read this...

    http://www.sata-io.org/namingguidelines.asp">http://www.sata-io.org/namingguidelines.asp
  • monsoon - Friday, February 2, 2007 - link

    Hello,

    I'm used to change computers frequently, I have lots of data to store.
    Currently I've got 4 external 300Gb drives and 4 external 400Gb drive; all of them connected through firewire.

    I've been looking eagerly for solutions similar to the NORCO DS-1220; but I need to connect the storage unit to laptops as well, so it has to control RAID5 all by itself.

    I can't find alternatives in the market, and while the UNRAID solution looks interesting, it's not safe, neither easy to implement.

    Looking forward to external storage devices reviews for home users with big archives.
    Units need to stand the test of time and be there while PCs come and go.
    Ideally, I must be able to replace drives with higher capacity when they get cheaper, without having to replace all of them at the same time.

    It better be silent; well, at least not loud...

    Any idea ?

    Thanks
  • mino - Saturday, February 3, 2007 - link

    Look for some reliable NAS solution (+Gbit swith - now dirt cheap).

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