Apple Xsan 1.1 - Manual (Page 27)

Chapter 2 Setting Up a Storage Area Network 27
 Spread file transfers across as many drives and RAID controllers as possible. Try
creating slices across the drives in RAID systems, then combine these slices into a
storage pool.
 To increase throughput, connect both ports on client Fibre Channel cards to the
fabric and set the multipathing method for the storage pool to Rotate.
 Store user files, file system metadata, and journal data on separate storage pools, and
create these storage pools using LUNs from different RAID controllers.
 Use a router to isolate the Ethernet network used by the SAN from a company
intranet or the Internet, or better, use a second Ethernet network (including a second
Ethernet card in each SAN computer) for the SAN.
 If your SAN uses directory services, mail services, or other services on a separate
server, use a second, separate Ethernet network to connect SAN computers to that
server.
 As a rule of thumb, consider that a single Xserve RAID controller, after file system
overhead, can transfer roughly 80 MB of user data per second (160 MB per Xserve
RAID system). If your SAN must support an application running on multiple clients
that requires specific throughput on each client, you can use this number to estimate
the number of Xserve RAID systems necessary to support the aggregate transfer rate.
Availability Considerations
If high availability is important for your data, set up at least one standby controller in
addition to your primary controller. Also, consider setting up dual Fibre Channel
connections between each client, controller, and storage device using redundant Fibre
Channel switches.
Important: Losing a metadata controller without a standby can result in the loss of all
data on a volume. A standby controller is recommended.
Also, if you have a standby controller, you can upgrade the Xsan software without
interrupting the SAN. For more information, see “Upgrading Controller Software” on
page 87.
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 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 assign user and group permissions to folders you create on a volume or
use standard file access permissions to control access to other items.