Checklist / experience of merging separate SAN Fabrics

[johnCatBE]

We're in the process of planning the merger of two distinct SAN circuits (each consisting of dual fabric circuits).

Originally they served different parts of business - one based on IBM Directors (Z/OS, IBM DS8100 storage and Pseries unix kit, the other Sun Solaris, Wintel HP Polyserve Matrix, HP EVA8100 storage.

Has anyone seen a step by step discussion of an approach to merging one fabric at a time?

We've harmonised IOD and switch firmware (6.0.0b). Domain ID's are not likely to conflict.

It is the intention to merge the zoning database from one switch on one fabric to another priot to making the connections.

I'd be interested in hearing other's experience of this and any obvious gotchas.

One concern (from previous issues when we've changed san attached tape drives is in preventing our Polyserve Matrix cluster hosts from rebooting!

thanks........John

[Amar_Joshi]

Hi John,

First let me tell you, fabric merge is tricky and not always works straight forward for anyone. On the other hand it's not very risky in situations where fabrics can't merge and fabrics remains isolated. It can cause interruptions when fabrics merge and new configuration takes place hence recommended to be scheduled in off-peak hours or with a proper downtime from business.

Follow the following steps as you prepare to merge SAN fabrics:
1. Check for conflicting Domain IDs on both fabrics before merging.
2. Check for conflicting zone definitions before merging.
3. Verify that the Fabric islands have the same feature licenses before merging.
4. Verify that all switch parameters are compatible with the fabric before merging.
5. Merge the fabrics using one ISL at a time.


Additionally, if you have access to any HP account rep, then pass on your fabric zone configuration (from both fabric) and they have a tool called SANToolBox which can compare the Zone configurations and will give you results whether 2 fabrics can merge or not.

Good luck and remember to prepare well to success.

[Bill Rothanburg]

John,

If you are running FICON with the Z/OS, check that your proposed topology won't violate those constraints.


If you have Fabric Manager, run the Fabric Merge Check. It does a pretty detailed check and will point out most problems. I'll use this when introducing a new switch to the fabric to ensure I have it correctly configured.


You will also want to check each Fabric's PID setting and confirm that the Domain IDs do not conflict. AIX and HP-UX server bind my PID and a changes in a Domain ID or the PID setting could affect these servers.


Get the ZoneMerger Tool from Brocade Connect. It will compare the zoning and allow you to manually copy the zones and aliases prior to the merge.

Bill

[johnCatBE]

Gentlemen

Many thanks for your comments - noted all.


Bill,

I've tried to search for the Brocade ZoneMerge tool via my Brocade Connect account, but have been unable to find anything.

Amardeep - your point of doing one ISL at a time - are you referring to simply one switch connection at a time, in our example via a single 4Gb/s SW link?

I'll keep a log of how things progress and post the checklist / experiences as things unfold.

[Sivakumar MJ._1]

Hi Wibidee,

Also take the configuration backup of all the switches before proceeding the fabric merge.

[Sivakumar MJ._1]

In order to "merge" two fabrics you require a Full Fabric License, Which allow you to construct ISL (inter-Switch
Links). Some times a 2-domain license come with the equipment, but if you
have more than two switches, the you need the full fabric in all of the
switches.

If you have support contract with Brocade, involve them in the activity..

[johnCatBE]

All

Thank you for your comments.
The process of performing the merge is now less of an issue than the potential effects of to the various kit attached to the SAN - Sun & Veritas clusters, HP Polyserve matrix, IBM P series AIX, VMWARE - quite a mixed bag.

This uncertainty - and the difficulty in testing - has led us to wonder whether we should consider the use of SAN routers to join the Fabrics rather than contemplate merger..............

Anyone using Brocade SAN routers to do this?

The standalone 7500 looks like it might be suitable and i gather there are Blade modules the fit the 48000 directors.

Regards John

[Bill Rothanburg]

I have a pair of Brocade 7500s that we use to route traffic via FCIP to a remote site. The FCR service works very well.

You are correct, there is a blade version called the FR4-18i.

If you don't need FCIP, you can also use one of the Brocade 8GB switches. These also support FCR.