Planning your san volumes – Apple Xsan 1.0 User Manual
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Chapter 2
Before You Begin
Planning Your SAN Volumes
It’s easy to add storage to an existing Xsan volume, but reorganizing a volume after you
set it up is not so 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 composed of:
•
Storage devices (usually Xserve RAID systems)
•
LUNs (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)
•
Underlying Fibre Channel and Ethernet networks
Before you use Xsan Admin to set up SAN volumes, decide how you want to organize
these components. Take the time to create a drawing or a table that organizes available
hardware into RAID arrays, storage pools, volumes, client computers, and controllers in
a way that meets both your users’ needs and your needs as SAN administrator.
First, consider these 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 your users require?
•
How important is constant availability?
•
What are your requirements for security?
Your answers to the above questions will help you decide the following:
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What RAID schemes should you use for your RAID arrays?
•
How many SAN volumes do you need?
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How should individual volumes be organized?
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Which LUNs go in each storage pool?
•
Which storage pools make up each volume?
•
Which clients, users, and groups should have access to each volume?
•
Which computers will act as controllers?
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Do you need standby controllers?
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Do you want to use controllers as clients also?
•
Where do you want to store file system metadata and journal data?
•
What allocation strategy should you use?
Review the considerations and guidelines on the following pages for help translating
your answers into a suitable SAN design.
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