I actually normally configure them for RAID5...typically 4 drives striped
and 1 drive parity. However, I've also setup 3 drives striped and 1 drive
parity. A little slower, but LOTS more reliable.
Now having said that, I've also done nutso and went crazy once and did a
mirrored RAID5 across two jbods...but this was a financial system that was
logging fund transfersso I figured we should be paranoid about it.
Can't remember what it was, but I think some folks call it RAID10.
/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 [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Sent: Wednesday, June 05, 2002 10:29 AM
Subject: Re: [luau] SANs
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:
H.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 destinationsif you have but one
server with one set of drives...then a switch is not necessarya
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 suchsame thing with a different name, different
protocol
with different amounts of overhead, etckeep in mind that if you
wanna
play your storage over IP...that you're paying for the IP
overhead1gb/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
wellbut 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 yeahmost fiber channel doodads are LC fiber connectors over
multimode
fiberthose suckers are VERY expensive cablesyou can also do sans
over copper which is LOTS cheaper, just change the gbicoh 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
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