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Do-It-Yourself Fibre Channel Array

Posted by timothy on from the woodscrews dept.

skarphedin writes "There's an interesting story here on a do-it-yourself fibre channel array. These guys make one for under $250 and it can perform up there with 15k SCSI in some cases." You know you want one.

6 of 149 comments (clear)

  1. Re:Store already slashdotted by tigress · · Score: 3, Informative

    Try eBay. We got a QLogic 2100 (Copper) for $40. Drives can be found for $99 for a tenpack of 18.2GB Seagate 10k drives.

  2. Only external? by larien · · Score: 4, Informative
    Since Fibre Channel is always found in external drive arrays
    Er, no, except perhaps in the Intel world. Sun certainly ships newer servers (280, 480, 880 & 1280) with FC internal disks. Their reason for that (given in their FAQ is that the arbitration for SCSI still takes place at the original 5MB/sec.
    1. Re:Only external? by hbackert · · Score: 4, Informative

      Starting at Ultra320, Quick Arbitration is now available.

      Given that this is cutting edge of parallel SCSI, I can understand Sun to skip anything older. However I yet have to see a significant performance gain from going from U2W (80 MB/s) to FC. Arbitriation might be slower on U2W, but FC contains routing informations in each packet, which parallel SCSI lacks.

      Personally, I am very happy with the good old parallel SCSI. Even cutting edge drives like Cheetah 15k.3 are really fast, even when I cannot push them to their limit.

  3. Re:Been there, almost done that... by tigress · · Score: 4, Informative

    Uhh, yes we DID get a host adapter for $40. =)

    QLogic 2100 copper, purchased on eBay for $32, shipping was about $8.

    Check it out yourself, there's some on there right now for less than $30.

  4. Re:I would like one! by sirwired · · Score: 3, Informative

    Optical fiber is not required for shorter distances, however, because Fibre Channel also works using coaxial cable and ordinary telephone twisted pair. Fibre Channel offers point-to-point, switched, and loop interfaces.

    Too bad whoever wrote that was completely full of it. Fibre Channel does not exist over coax or twisted pair.

    Coax really isn't used much for data cabling any more.

    Twisted Pair? Who knows. I expect the error rates are too high for the extremely tight specs required by Fibre Channel.

    SirWired

  5. SCSI vs. Fiber Channel by snowtigger · · Score: 5, Informative

    Where I used to work, we had a few Sun servers with FC disk arrays.

    Here's the Sun engineer's explanation of why FC is so interesting for servers:

    1) The FC protocol has a 100MByte/s dedicated bandwidth to data. The communication between disks etc. will not interfer with this bandwidth.

    2) Modern SCSI has two modes: one for data (burst mode) and one communication mode. The communication mode is a lot slower (first scsi standard) in order to remain compatible with older disks. This means that scsi is a lot more advantageous to users reading large files than small files.

    This is where FC becomes interesting: If you have a striped disk array, you will read many small segments from different disks instead of large segments from single disks. In this special case, FC is faster than SCSI, even though it is "slower" by looking at the burst rates in the specs.