It’s easy to add storage to an Xsan SAN, but reorganizing a SAN after you set it up isn’t simple. So, it’s important to plan the layout and organization of your SAN and its storage before you set it up.
An Xsan SAN is made up of:
Storage devices (RAID systems)
LUNs (SCSI logical unit numbers, usually RAID arrays)
Storage pools (groups of LUNs)
Volumes (groups of storage pools visible to users)
Clients (computers that use volumes)
Controllers (computers that manage volume metadata)
An Ethernet network used to exchange volume metadata
Before you set up a SAN, you must decide how to organize these components. Take the time to create a diagram or a table that organizes available hardware into RAID arrays, volumes, client computers, and metadata controllers in a way that meets SAN users’ needs and your needs as the SAN administrator.
Preliminary planning questions
As you plan, consider the following questions:
How much storage do you need?
How do you want to present available storage to users?
What storage organization makes the most sense for user workflow?
What levels of performance do users require?
How important is high availability?
What are your requirements for security?
Your answers to the questions above will help you decide the following:
What RAID schemes should you use for your RAID arrays?
How many SAN volumes do you need?
How should individual volumes be organized?
Which clients, users, and groups should have access to each volume?
Which computers will act as metadata controllers?
Do you need standby metadata controllers?
Do you need to adjust a volume’s allocation strategy?
How should you configure your Ethernet network?