Qlogic SAN setup/zoning questions

Posted on 2009-04-28
Medium Priority
Last Modified: 2013-11-14
We have an Apple XServe RAID (XRaid) which is currently directly connected to a Mac computer.  We want to have the ability to connect a second Mac to the XRaid.  I know that two Macs can't access the same volume simultaneously - we would dismount the volume on Mac 1 and then mount on Mac 2 and vice versa.

We have purchased a Qlogic 5602Q fiber channel switch and all the cables/transceivers/cards necessary to physically hook both Macs amd the Xraid up to the switch.  What do I need to do on the switch as far as configuration so that both Macs will be able to see both of the XRaid controllers?
Question by:FWeston
  • 2

Expert Comment

ID: 24272718
I don't know Apple XRaid, but  I know something about SAN.

Generally speaking, 2 computers cannot access same volume :
this is not in the sense that "they are not able to",
but is in the sense: "they have not to access same volume":

if they do, before or after the partition inside volume, will be corrupted.

Two or more hosts can access (in the sense "is allowed") to a same volume,
(using FC switch as you have got), ONLY if they use a software
that synchronize them, as Cluster, Virtualizzation, or other.

If you need share files, you have to permit access to the SAN, just to 1 server:
this, after, using own File Sharing protocol, (NFS for Unix, SMB for Windows,...)
will share documents to other servers.

Do you agree ?

You can wire both Macs to the Storage, via Switches, but on the Storage, you
have to mask each volume to each wwname of the HBA/Macs.

How many HBA or port per HBA have you each MAC ?


Author Comment

ID: 24279478

I already know that they won't both be able to access the same volume at the same time.  As I've said, I need to allow both Macs the ability to see each volume with the understanding that only one will be able to have it mounted at any given time.

Each Mac has one dual-port HBA.


Accepted Solution

dolomiti earned 2000 total points
ID: 24281327
thank you for answer, and clarity.

Usually to connect a dual-controller Storage with dual-channel HBAs or 2 HBA/server,
2 FC-Switches is used.
Suppose we have two FC-Switches and each FC-Switch has 10 ports

See Solution Alpha in the snippet.

This is physical FC schema, where <======> are FC cables (six).
Done this, you have to zone the Switches; you can zone by wwname
or port number. Suppose you choose PortNumber

On SwitchA, you create 2 zones:

Zone_1 = Port10,Port_1
Zone_2 = Port10,Port_2

On SwitchB, you create 2 zones (same names, same ports) :

Zone_1 = Port10,Port_1
Zone_2 = Port10,Port_2

If you have just one switch, there is no problem;
you have just a single point of failure if Swich fails.
Consider to use ports 11-20 of your switch as port 1-10 of Switch(B)  (See solution Beta)

On this switch, define 4 zones:

Zone_1 = Port10-Port_1
Zone_2 = Port10-Port_2
Zone11 = Port20-Port11
Zone12 = Port20-Port12

That's all ? No!

>>>>>> On the storage,  you have to define
- 2 or more Logical Volumes
- 2 hosts, and attached each host, the wwname of the 2 ports


You can find HBA's wwname in many ways:
* Reading physically on the HBAs
* See on Hosts by specific program (also Qlogic ones)
* At bios level
* On the Storage (not always possible) , if you attach one at time and note wwname and/or put in group

- Share each Volume to 1 host (create the LUN)

Volume1(  music  )--->Host1 = LUN_0
Volume2(pictures)--->Host1 = LUN_1

Volume3(  video  )--->Host2 = LUN_0

>>>>>> On the server you need:
- Device driver for HBA
- Multi-path Software

if you don't install the first, you will not see any disk
if you don't install the last, you'll see each Volume 2 times,

but knowing Apple (just as end-user), I believe all will be easy and perfect as use an IPod.


                S O L U T I O N   Alpha:   two switches
/-------\                                                      /-------\
|       |                                                      |       |
!     1 +<=============> HBA(a)-Host(1)-HBA(b) <=============> + 1     |
! S   2 +<=============> HBA(a)-Host(2)-HBA(b) <=============> + 2   S |
! w   3 |                                                      | 3   w |
! i   4 |                                                      | 4   i |
! t   5 |                                                      | 5   t |
! c   6 |                                                      | 6   c |
! h   7 |                                                      | 7   h |
!     8 |                                                      | 8     |
!(A)  9 |         /--------------\   /--------------\          | 9  (B)|
!    10 +<=======>+ Controller(a)|   | Controller(b)+<=======> +10     |
|       |         \--------------/   \--------------/          |       |
\------/                                                       \-------/ 
    o o o o o o o o o o o o o o o o o o o o o o o o o o o o o
                 S O L U T I O N   Beta: one Switch
/-------\                                                      ~~~~~~~~~
|       |                                                      |       |
!     1 +<=============> HBA(a)-Host(1)-HBA(b) <=============> +11     |
! S   2 +<=============> HBA(a)-Host(2)-HBA(b) <=============> +12   S |
! w   3 |                                                      |13   w |
! i   4 |                                                      |14   i |
! t   5 |                                                      |15   t |
! c   6 |                                                      |16   c |
! h   7 |                                                      |17   h |
!     8 |                                                      |18     |
!     9 |         /--------------\   /--------------\          |19     |
!    10 +<=======>+ Controller(a)|   | Controller(b)+<=======> +20     |
|       |         \--------------/   \--------------/          |       |
~~~~~~~~~                                                      \-------/ 

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