topic Re: design fabric and interswitch in HPE EVA Storage

design fabric and interswitch

Pol_4 — Mon, 22 Mar 2004 06:45:35 GMT

hi,

I'm planning a new configuration for a brand new san, with eva3000 and 4 unix servers, along with 2 FC EL16/2 switches and 2hba in each server. The question is :
- do I need to plan links between the two switches ?
- do I need to plan 1 fabric or two ??
- do I need to use one zone per host ?? per hba ??

Re: design fabric and interswitch

Uwe Zessin — Mon, 22 Mar 2004 06:54:37 GMT

Pol,
a 'high availability' design uses two different fabrics - in your case both switches would not be connected and each switch be a fabric on its own.

The Storage Management Appliance (SMA) that is used to manage the EVA requires that it be 'zoned out' from the server's fibre channel adapters (FCAs). It depends on your operating system if you can put all FCAs in one zone or not. I would put each FCA in a zone of its own to minimize any effects.

Remember that unless you are using the Tru64 Unix version 5 operating system you also need the Secure Path software.

Re: design fabric and interswitch

Peter Mattei — Mon, 22 Mar 2004 07:26:34 GMT

To achieve high availability you need to build 2 independent SANs. Most failures in a SAN come from manual interventions mostly wrong commands (zoning etc.)
By having two SANs with 2 HBAs per server going to two controllers in an EVA you also have redundancy in case you loose a component like cable, HBA, power to a switch etc.

Also see the SAN Design guide on http://www.hp.com/go/sandesign
Starting on page 141 you will find a detailed description on how to set your EVA SAN up.

Cheers
Peter

Re: design fabric and interswitch

Pol_4 — Mon, 22 Mar 2004 09:48:43 GMT

thank you for the quick answer and the infos.
I already had a look at this guide but I could not find easily the infos about the two fabrics construct.

Re: design fabric and interswitch

Peter Mattei — Mon, 22 Mar 2004 11:59:36 GMT

What about some points?

Re: design fabric and interswitch

Uwe Zessin — Mon, 22 Mar 2004 12:18:42 GMT

Pol,
with two switches you automatically have two fabrics as long as you do not connect the switches. Page 142 of the SAN Design Reference Guide (AA-RMPNL-TE) that Peter has mentioned has pictures about the cabeling.

Please try to be a bit more verbose when asking a question - we cannot read your mind. What information do you need to continue? Note that 'everything' is not a valid answer ;-)

Re: design fabric and interswitch

Leif Halvarsson_2 — Mon, 22 Mar 2004 15:18:06 GMT

Hi,
There is many ideas about zoning, e.g.:
- Zoning per HBA
- Zoning per application
- Zoning per OS
- Soft or Hard zoning.

If all your servers is running the same OS and you have only one storage system, it is perhaps easiest to put all servers in one zone and just create one more zone for the management appliance server.

Re: design fabric and interswitch

Mike Naime — Mon, 22 Mar 2004 21:14:29 GMT

Pol:

1.) NO! DO not connect the 2 SAN switches. you want seperate redundant paths to your storage.

2.) Plan for 2 fabrics.

3.) Do you plan on growing this SAN fabric in the future? If Yes, then get the full 16/2 switch and not the EL version. Zoning is then a must.

If you are not planning to grow this SAN, then you will be OK with the EL version, and you do not NEED to zone anything on the SAN switches. Strongly recommended, but not absolutely necessary.

If you are zoning:
1 zone per HBA = 2 zones per host. One zone in each fabric.

Mike Naime
Your Milage may vary.

Re: design fabric and interswitch

Tarmo Linnam?gi — Tue, 23 Mar 2004 02:06:44 GMT

Hello

OK - if people are so sure then don't interconnect switches. I always do since when the zoning is done right it does not increase the availability and gives you a lot easier administration.

Zoning - aliases which include WWN-s of a host, or a storage etc...
Zones contain only devices on the need to see basis - so for a server it will be server alias (contains server FCA WWN-s) and storage alias (contains storage WWN-s).
Sometimes you need to add there some network storage router for backup also...

BR

Tarmo