Apple Xsan 2 (Third Edition) - Manual (Page 25)

Chapter 2 Planning a Storage Area Network 25
Important: If you create users and groups on each SAN computer, be sure that:
Each user or group has a numeric user ID (UID) or group ID (GID) that is unique Â
throughout the SAN
Each user or group defined on more than one computer has the same UID or GID
Â
on each computer
Outgoing Mail Service
Xsan can send SAN status notifications via email on your local network (IP subnet)
without using a separate mail server. However, depending on your network
configuration, you may need an SMTP server to send notifications outside your local
network.
If you don’t have access to an outgoing mail server, use the mail service in
Mac OS X Server to set one up. For information, see Mail Service Administration at
www.apple.com/server/resources/.
Planning Your SAN
It’s easy to add storage to an existing 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) Â
LUNs (SCSI logical unit numbers, usually RAID arrays) Â
Storage pools (groups of LUNs) Â
Affinity tags, which identify storage pools with similar performance and data Â
protection
Volumes (groups of storage pools visible to users)
Â
Clients (computers that use volumes) Â
Controllers (computers that manage volume metadata) Â
An Ethernet network used to exchange volume metadata Â
A Fibre Channel network used to transfer data to and from volumes Â
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.
You don’t need to plan your storage pools or affinity tags if you set up each volume
using a preset volume type based on the kind of work the volume supports.