Apple Xsan 1.4 - Manual (Page 41)

Chapter 2 Setting Up a Storage Area Network 41
Planning Considerations and Guidelines
The following paragraphs might help you make some of your SAN design decisions.
How Much Storage?
Because it’s easy to add storage to an Xsan SAN, you only need to decide on an
adequate starting point. You can then add storage for user data as needed.
You can’t expand a storage pool that is used to store volume metadata and journal
data. For information about estimating your metadata and journal data storage
requirements, see “Estimating Metadata and Journal Data Storage Needs” on page 50.
Note that the number of Xserve RAID systems you use affects not only available space
but also SAN performance. See “Performance Considerations,” below.
How Should Users See Available Storage?
If you want the users working on a particular project to see a volume dedicated to their
work, create a separate volume for each project. If it’s acceptable for a user to see a
folder for his or her work on a volume with other peoples’ folders, you can create a
single volume and organize it into project folders.
Workflow Considerations
How much file sharing is required by your users’ workflow? If, for example, different
users or groups work on the same files, either simultaneously or in sequence, it makes
sense to store those files on a single volume to avoid having to maintain or hand off
copies. Xsan uses file locking to manage shared access to a single copy of the files.