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SAN - Switchces really needed in a two server config?

TedgCl
TedgCl asked
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I have two servers and a fibre channel SAN array with two fibre channel controlers.

I have slide 26:
http://h20195.www2.hp.com/V2/GetPDF.aspx/4AA2-5505ENW.pdf

Do I really need a fibre channel switch?  Can't I just hook up the servers directly to the SAN? What's the advantage to having one or two fibre channel switches like they show in the picture with only two servers?

Thanks!
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gsmartinManager of IT

Commented:
Connecting directly to a FC SAN array is certainly possible, but not a typical approach for a SAN.  This type of connectivity is typically referred to as Direct attached storage and/or a Cluster Storage configuration.  

SAN arrays usually involve at least one Fibre Channel switch that enables you to share storage amongst multiple servers and provide room for adding more servers.  The purpose of having two FC switches is for redundancy (FC Link, SAN Fabric, GBIC, and FC SAN Controller Redundancy).  Depending on how critical of a role your SAN plays in your environment should help you determine wither you need one or two Fibre Channel switches.  Especially, if your SAN is being used for corporate resources (like mail, Active Directory, File shares) virtualization, Boot from SAN, Production, etc...  Any of these areas are usually critical enough to guarantee their uptime.  

Over the years, I've had many SANs and have experienced various issues.  Given my experiences any Corporate or Production SAN I put in place always is part of a redundant FC switch configuration; primarily when they are supporting critical environments.  Depending on the size of your environment, the role the SAN plays, and how the Business reacts to system outages are some things to consider.
Distinguished Expert 2019
Commented:
P2000 MSA supports "direct" connection, see pages 37-39 in the user guide. http://bizsupport1.austin.hp.com/bc/docs/support/SupportManual/c02010751/c02010751.pdf 

Be careful of the terminology, although it's wired point to point it's logically running "arbitrated loop" but when connected via switches it may be termed "direct" since it isn't a loop. You'll notice that on the fibre channel HBAs terminology.

If you only have two servers why not use SAS host connectivity rather than fibre channel? Supports up to 4 hosts in a non-switched configuration since each controller has 4 host ports.