Scott,
Excellent question. I assumed, possibly incorrectly,
that cost would be major criteria given the tight budgets at our institutions
of higher learning. Clustering and
mirroring with Vfilers are excellent solutions, but they tend to press on
limited budgets.
A pure hardware solution, while not
elegant, has minimal cost, provides very short MTTR and minimal operating complexity.
With the limited number of shelves on each
system a clustered environment may require more shelves and associated disks to
preserve a boot OS environment on both machines.
Hunter
Hunter M. Wylie
Bus: 503-633-8900
FAX: 503-633-8901
Cell: 503-880-1947
-----Original Message-----
From: Waters, G Scott DSTI
[mailto:george.scott.waters@us.army.mil]
Sent:
To: 'Hunter Wylie'; 'Michael
Homa'; 'toasters@mathworks.com'
Subject: RE: Duplicating filers
Why not just look at clustering the two filers??
... or am I missing something?
- Scott W.
-----Original Message-----
From: Hunter Wylie [mailto:hwylie@stpaultel.com]
Sent: Thursday, April 24, 2003 2:36
PM
To: 'Michael Homa';
toasters@mathworks.com
Subject: RE: Duplicating filers
Michael,
In theory it might work on a
"perfect" day "but" the number and type of simple failure
scenarios would make the perfect day highly improbable. I suggest you take a
simpler approach that many of my very large customers use to achieve very
high availability, very short mean time to repair, simplicity and low cost.
Buy a used F740 (head) configured like the biggest one
you have, a spare 36 and 18 GB disk and a FC9 disk shelf. When something
breaks and you have an idea it's "head associated - down the dying F740
and power it off, unhook LAN connections, FC disk cable, etc. and attach them
to the spare F740 racked between the original two heads. Cable lengths can get
you if you are not careful. Watch your power load on the rack/circuit.
If it is shelf associated, shut down the system, power
it down, remove the old shelf cable and attach the new one, move all the drives
and power up.
In both cases the system will comeback on line with
all the old identities re-established, no DNS hacks.
This technique is used by one of the largest on-line
retailers in the world. They love it.
No software licenses are needed on the spare system as
long as it is "NEVER" used in parallel production with the two other
systems. In this
mode it is strictly a replacement spare
part. If you want to use it in
any other mode you must acquire
software licenses with it.
The nice thing about this solution is it is simple to
test.
Send me an email if you want to figure out the exact
parts you will need.
Hunter M. Wylie
21193 French Prairie Rd
St. Paul, Oregon 97137
Bus: 503-633-8900
FAX: 503-633-8901
Cell: 503-880-1947
-----Original Message-----
From: owner-toasters@mathworks.com
[mailto:owner-toasters@mathworks.com]
On Behalf Of Michael Homa
Sent: Thursday, April 24, 2003
10:24 AM
To: toasters@mathworks.com
Subject: Duplicating filers
Hi.
My name is Michael Homa and I'm a member of the
Systems Group at the University of Illinois at Chicago.
Some background
---------------
We have two F740 filers: netapp1 and netapp2.
o Both of them are at ONTAP
6.2.1.
o Each has a different admin
host.
o Both have two FC9 data
shelves. On netapp1, one shelf contains 18GB
drives; the
other shelf, 36GB drives. On netapp2, both shelves
have 36GB
drives.
o Netapp1 has one volume,
vol0, and two raid groups, rg0 and rg1.
o Netapp2 has two volumes,
volboot and vol0, and each volume has a
single raid
group, rg0.
Netapp1 is the "center of our universe" and
is NFS-mounted to almost all of our production servers. Netapp2 currently
functions solely as the recipient of the snapmirroring of netapp1.
I've been asked to undertake a project in which I make
netapp2 be a duplicate of netapp1. In the event that netapp1 becomes
unavailable (maybe a catastrophic hardware failure), we want to re-cable
netapp2 to the network, monkey with DNS, and reboot the box. In effect, for all
intents and purposes, make it netapp1.
It's a good idea in theory but maybe in practice it
won't work out. Nope. Now that I think about it, it doesn't even sound like a
good idea in theory but my boss has asked me to try it so what the heck.
Has anyone attempted this? I'm looking for
suggestions, ideas, "gotchas." I don't need to reinvent the wheel;
I'm more than willing to learn (borrow, steal) from others.
Thanks.
Michael Homa
Academic Computing and
Communication Center
University of Illinois at Chicago
email: mhoma@uic.edu