> -----Original Message----- > From: fedora-list-admin@xxxxxxxxxx > [mailto:fedora-list-admin@xxxxxxxxxx]On Behalf Of Henry Hartley > At the risk of starting a religious flame war, could you comment on > the relative performance of hardware RAID in IDE vs. SCSI? For the > sake of argument, assume top of the line hardware in both. Does > hardware IDE RAID perform as well as hardware SCSI RAID, all else > being equal (but is it ever?)? First of all, my experience with IDE RAID, is, for the most part, theoretical; I've done a lot of reading, but only have a single low-end RAID card for myself. For a RAID-on-a-card solution, I believe that SCSI RAID controllers are still superior (but for a given price point the performance is probably close). If I were implementing an IDE RAID solution, I'd use one of the external RAID solutions available from companies like Electronix (www.raidweb.com), which uses IDE disks, but interfaces to the server via a SCSI-3 or fiber bus. > What factor does rotation speed play? That is, how will an array > of 16 7,500 RPM drives compare with an array of 8 15,000 RPM > drives? For raw transfer rate, the difference shouldn't be too significant; 7200 RPM EIDE disks can already transfer at >40MB/sec; multiply that by 16 and you've maxed out any bus technology currently extant. However, for seek time, the difference can be significant. > I assume the SCSI solution will be more expensive but how much? > Will the performance make it worth the extra expense? There is a > time to be cheap and a time to spend money, Proverbs 3:6 (more or > less). Figure at least double the cost of an equivalent IDE system, that's assuming highest end IDE (WD raptors) vs. equivalent (10K) SCSI. > The specific function for my array will be in a terminal server > where many workstations are using the same drive array. The > cost of the server is expected to be high but won't come close > to the savings on workstation hardware. I can afford to be > (cannot afford NOT to be) a bit extravagant on the server - fast > CPUs, lots of RAM, big, fast RAID array... If you're planning on going with RAID 5, I'd go with SCSI, since the RAID technology is more mature there, and you'll have a wider choice of cards, many of which will outperform the 3ware cards. If you can do RAID 10, then a 3ware 8506-12 with 12 WD raptors would probably be a good solution, but you might have to build the system yourself; I haven't seen a lot of commercially available IDE servers out yet. Actually, I just did a quick check of SCSI vs IDE 10K 36GB disk prices on Pricewatch, and the prices are comparable. I guess that until 10k drives become more of a commodity, there may not be any great savings. HTH. Steve
