Apple Xsan 1.4 - Manual (Page 44)

44 Chapter 2 Setting Up a Storage Area Network
Security Considerations
If your SAN will support projects that need to be completely secure and isolated from
each other, you can create separate volumes for each project to eliminate any
possibility of the wrong client or user accessing files stored on a volume.
As the SAN administrator, you control which client computers can use a volume. Clients
can’t browse for or mount SAN volumes on their own. You use Xsan Admin to specify
which clients a volume is mounted on.
You can also set up access control lists (ACLs) in Workgroup Manager or assign user
and group permissions to folders using standard file access permissions in the Finder.
Choosing RAID Schemes for LUNs
Much of the reliability and recoverability of data on a SAN is not provided by Xsan itself
but by the RAID arrays you combine to create your storage pools and volumes. Before
you set up a SAN, you use the RAID Admin application to prepare LUNs based on
specific RAID schemes.
Important: If a LUN belonging to an Xsan volume fails and can’t be recovered, all data
on the volume is lost. It is strongly recommended that you use only redundant LUNs
(LUNs based on RAID schemes other than RAID 0) to create your Xsan volumes.
LUNs configured as RAID 0 arrays (striping only) or LUNs based on single drives are
difficult or impossible to recover if they fail. Unprotected LUNs such as these should
only be used for volumes that contain scratch files or other data that you can afford
to lose.
Xserve RAID systems ship already configured as recoverable RAID 5 arrays.