Thanks Brian, Question, as I understand it, these arrays are typically set to RAID-0 for striping across the drives, thereby increasing throughput. Assuming this is correct, do you know how many drives are required, or typically required, for this?
-Charles On Tue, 4 Jun 2002, Brian Chee wrote: > Hmmmm.....let's see how well this can be done in a nutshell.... > > SAN's come in several flavors, but the idea is that from a 64bit cards > (yup...if you ain't got 64bit PCI slots, you're not going to get anything > better than ultra160) you travel over a fiber optic path to either a switch > or a hub. Just like data networks a switch is a good idea if you have a > multipath environment with multiple destinations....if you have but one > server with one set of drives...then a switch is not necessary....a single > HBA (fiber channel comes 1mb/sec or 2mb/sec) to an elcheapo hub to the jbod > (just a bunch of disks) is pretty inexpensive and gives you the terrific > throughput that folks like about sans. > > Now iscsi and such....same thing with a different name, different protocol > with different amounts of overhead, etc....keep in mind that if you wanna > play your storage over IP...that you're paying for the IP > overhead....1gb/sec fiberchannel is faster than storage over Gig-ethernet > due to overhead. > > Linux is supported well by qlogic and compaq is a relabeled qlogic card (may > have changed...heard rumblings about emulex too).....interphase had great > cards (gib+fiber channel) but I'm not sure they're around anymore???? > > I've run qlogic cards in solaris, linux and NT...they all work well....but a > switch is necessary only if you're mixing several systems and have to carve > up your array into several pieces.....but if only one system and one set of > drives (can be multiple jbods) then a hub is fine. Emulex makes fine cards > and hubs.... > > Oh yeah....most fiber channel doodads are LC fiber connectors over multimode > fiber....those suckers are VERY expensive cables....you can also do sans > over copper which is LOTS cheaper, just change the gbic....oh yeah, a > gigabit ethernet SX fiber gbic is exactly the same at layer1 as fiber > channel 1gig.....they are interchangable.... > > /brian chee > > University of Hawaii ICS Dept > Advanced Network Computing Lab > 1680 East West Road, POST rm 311 > Honolulu, HI 96822 > 808-956-5797 voice, 808-956-5175 fax >
