Fibre Channel (SAN)

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Occasional Contributor
Posts: 7
Registered: ‎06-29-2010

Creating Fiber Mesh

Hi All,

I have been tasked with bringing together 2 separate vmWare environments.  Both environments are in full production. Looking for insight.

Environment 1:

2 x Brocade 200E Fiber switches.  (The switches are not connected to each other).

ESX hosts HBA's connected to each switch

2 x EMC Sans

Environment 2:

2 x IBM 2005 16B Fiber switches (Again the switches are not connected to each other)

ESX hosts HBA's connected to each switch

1 x IBM SAN

The goal(s) are as follows:

1. Interconnect both environments so that all ESX hosts have access to all SANs

2. Introduce a new SAN to environment 1

3. Migrate all data from the IBM SAN in environment 2 to the new SAN in environment 1

4. Decommission the fiber switches and SAN in environment 1.

I have attached a jpg depicting the current and proposed layout.

My concern is of course that this is your typically critical production environment. Research seems to imply that creating the mesh is simply a matter of plugging in the cables and the ports will autoconfigure.  Is this a gross oversimplification?

Thank you all so much in advance for your help and guidance!

Super Contributor
Posts: 260
Registered: ‎04-09-2008

Re: Creating Fiber Mesh

>>My concern is of course that this is your typically critical production  environment. Research seems to imply that creating the mesh is simply a  matter of >>plugging in the cables and the ports will autoconfigure.  Is  this a gross oversimplification?

What you say about the ports is correct but there are lots of other things. Primarily you need to lookout for flow control parameters in both environments and also match the zoning information to create one single config. I also do not agree with your strategy of creating a mesh. My suggestion would be to

1. Install a new SAN with 2 core switches. Connect ports of existing storage or the new storage to the new SAN.

Connect the ESX servers to these switches on a single path and present LUNs.

Migrate the data. The only risk is that during the change window your ESX hosts are on a single path.

2. Once the ESX hosts are on new storage infra. Re-Configure the old switches and introduce them to the new SAN as edge switches.

Occasional Contributor
Posts: 7
Registered: ‎06-29-2010

Re: Creating Fiber Mesh

Thank you for taking the time to respond.  I do have a few more questions:

  • What is it about the mesh topology being proposed that you do not agree with?
  • If I connect the additional fiber cables to create the mesh as depicted in the diagram will there be any immediate impact?  Or is it completely benign until I start creating zones?
  • Do I need any additional licensing for this setup?
  • What are the risks I need to be aware or a work to mitigate prior to proceeding?

Thanks again.

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Creating Fiber Mesh

you have 2 fabrics.fab-1 and Fab-2, fab 2 is the redundant of fab-1, both the Fabrics must have different configurations. in fab-1, the name of the config file is different and in fab-2 also config file is different. Like this you have 2 SANs, How you will merge these by mesh topology. It will give you error because of config files are different.

In order to remove SAN1,

There should be enough ports in SAN 2.

Need the downtime from SAN1, move the ports one by one to SAN 2, do the zoning again in SAN2, check the paths and everything, then remove SAN1.

For SW merging thorugh ISLs you need atleast fabric Licenses on both the SWs, Full or 4 domain license.for ISl/Trunking you need trunking License.

This is the best and safest way.

Do not try to make it in mesh, zone conflict will be there while connecting 2 SWs together through ISlLs.

If you need any info pls put it here.

Occasional Contributor
Posts: 7
Registered: ‎06-29-2010

Re: Creating Fiber Mesh

Thanks Hemant!  Presently the the 2 fabrics are completely separate as depicted in the diagram.  Are you saying that if I add the new cabling to connect the 2 fabrics I will get an error?  So what do I need to do to make it happen?  It looks like your post may have been cut off.

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Creating Fiber Mesh

I have corrected it again. pls mak ethe thread correct if you find it.

pls find the pdf for SAN migration guide.

Occasional Contributor
Posts: 7
Registered: ‎06-29-2010

Re: Creating Fiber Mesh

Thanks Again,

For some reason trying to view the PDF gives internal server error on the web page.  Nevertheless, I'm still not quite clear here.  If you wouldn't mind, let's just forget about the removal of the SAN for the time being.  Lets just focus on getting all all ESX servers to see all SANs.  If I can get it that far I think I will ber okay.  This is why I was looking at meshing, I figured I just plugin the cables, create the zones and I'd be okay.  Clearly this is not the case.  If you wouldn't mind explaining I'd me grateful.  If there is a much simpler way as you seem to imply please do explain.  Thank you for your time.

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Creating Fiber Mesh

If you want to migrate data from SAN1 to SAN 2 then you have to take complete back up o fthe data, then take downtime, disconnect all the devices from SAN1, put them in SAN2, do the zoning  again ( SAN 1 hosts with SAN 1 Storage, SAN1 host with SAN 2 storage and SAN 2 hosts with SAN 1 Storage)

By this way only all your hosts will be able to see all the storages in SAN2.You can remove SAN1 SWs now.

and if you want vice versa, you have to in the same way.

You can not merge 2 independent redundant SANs. This will give you zone conflict.

Otherwise as Biju says one path migartion.

But the above is the best one if you have enough ports.

pls find attached again the pdf:

Occasional Contributor
Posts: 7
Registered: ‎06-29-2010

Re: Creating Fiber Mesh

Ok...I am definitely not explaining myself properly.  I don't want to merge the SAN's.  I want to merge the fabrics (for lack of a better word).  Right now it is like this:

Environment 1:

ESX

Fiber Switch

SAN

Environment 2:

ESX

Fiber Switch

SAN

ESX hosts in Environment 1 cannot see SAN/LUNS in Environment 2 and vice versa.  There is no cabling connecting Environment 1 to Environment 2.   I want to change this so that ESX hosts in either environment can see LUNS on either of the SANs.

PDF doesn't work still.  I think its a problem with the site becasue I was trying to upload a PDF diagram last night with the same result.  Ultimately had to use jpg as it was all that would work.

Super Contributor
Posts: 425
Registered: ‎03-03-2010

Re: Creating Fiber Mesh

mark, I have written it clearly, that whether it is ESX or Storage, those will not be able to see unless those are connected locally or through ISLs. In your case SAN 1 devices will not be able to access SAN 2 devices, unless until those are connected to SAN 2 and zoned with SAN 2 or SAN 2 should be interconnected through ISLs to SAN 1.

In your case SAN 1 can not be interconnetced to SAN 2 because of 2 different fabrics and their configuration. you can no tmerge the 2 SANs. No way, only way is to tak ethe down time of SAN 1 and connect all the devices to SAN 2 and  do the rezoning as I have mentioned above.

2 Independent SANs can not be merged together.

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