[luau] SANs

[Brian Chee]

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

----- Original Message -----
From: "Charles Lockhart" <lockhart at jeans.ifa.hawaii.edu>
To: "luau" <luau at videl.ics.hawaii.edu>
Sent: Tuesday, June 04, 2002 7:22 PM
Subject: [luau] SANs


>
> Ok, hoping you guys may know more about storage area networks than I do
> (not difficult, I don't know much ;o).  I'm working on an instrument
> that'll require some kind of SAN to store and redistribute a fairly high
> bandwidth data stream.
>
> As I understand it, there are two general types of SANs, the older fibre
> channel ones and some newer ones that use alternate connections (something
> about TOE, tcp off-load engines).  The idea is that the older ones, I
> think, use a semi or completely proprietary protocol, and the newer ones
> can use something more generic, like gigabit ethernet.
>
> Does anybody know how easy these are to integrate, any place that has
> particularly good ones, from either school?  Right now we're looking at
> a compaq solution that uses the fibre channel stuffs, but we need to look
> at both other fibre channel alternatives and the newer alternatives.
>
> -Charles
>
> _______________________________________________
> LUAU mailing list
> LUAU at videl.ics.hawaii.edu
> http://videl.ics.hawaii.edu/mailman/listinfo/luau