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SAN server accommodation

How many servers can a SAN accommodate?

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Rather than simply blurting out a theoretical or architectural limit of a specific interface, protocol, product or vendor rule of thumb, the answer is that it varies. There are several things that determine how many servers a SAN can accommodate, including the type of SAN (Fibre Channel or iSCSI), topologies, types of applications, service level requirements (performance, availability, capacity, etc.) and specific vendor products, among others. Talk with your vendors or solution providers about your environment and specific technologies in use..

I would not be surprised if they come back with different responses given all of the different variables. Some general questions to consider in addition to those already mentioned include:

  • Is this a single SAN or multiple SANs that are segmented?
  • What are the performance characteristics of the servers and applications?
  • How much storage needs to be accessed by the servers?
  • What is the topology and allocation of ports and performance?
  • What are your, or your vendor's, server-to-storage port ratios?
  • What level of redundancy and availability do you need>

This was first published in March 2007