Topology Example 2

In this larger implementation, we have six clients accessing a total of 7.28 TB of storage. The SAN's bandwidth availability is roughly 320 to 400 MB/s. This SAN is connected to an outer network, shown in green. Notice that all trivial Ethernet components are routed to this outer network, and only the nodes of the SAN are on the metadata network. Further, we have a standby metadata controller available to take over MDC duties if the primary MDC fails. For directory services, we have three choices:

The primary MDC is the open directory master of the SAN, with the standby MDC as a replica.
The standby MDC is the open directory master of the SAN, with the primary MDC as the replica.
The directory has been moved to the outer network, thereby allowing the Xserve units to just be MDCs (recommended).

Storage

2 x Xserve RAID 5.6 TB ( populated with six 400 GB drive modules per controller; the seventh is a hot spare, not used in the storage calculation)
512 MB cache per controller (1 GB total)

Fibre Channel Switch

1 x Apple qualified Fibre Channel switch

Metadata Controllers

Xserve, Xserve G5, or Xserve G5 cluster node
1 GB RAM per controller
Apple Fibre Channel PCI-X card
Mac OS X Server v10.3.6 or later
Apple Xsan software
PCI video card (optional)

Metadata Network

1 x unmanaged gigabit Ethernet switch

Client Workstations

Power Macintosh G5 or Power Macintosh G4 Dual 800 or faster
Apple Fibre Channel PCI-X card
Apple Ethernet PCI-X card
Mac OS X v10.3.6 or later
Apple Xsan software

Outer Network

Mac OS X Server running Open Directory to provide directory services, or a system running a similar service such as Microsoft Active Directory.

Topology Example 3

In this topology, ten clients share 16 TB of storage. The SAN's bandwidth availability with four semi- populated Xserve RAIDs is a whopping 640 to 800 MB/s. Because of the number of Fibre cables in this topology (32 total), an additional switch has been implemented. Data cascades effortlessly between the two switches because a high-bandwidth interswitch link (ISL) has been made with six user ports on each switch. Think of it as a data river that flows bidirectionally between each switch. A primary and a standby MDC are mandatory with such a large implementation. To keep their roles simple and efficient, the directory is implemented on the outer network.

Storage

4 x Xserve RAID 7 TB (populated with six 500 GB drive modules per controller; the seventh is a hot spare, not used in the storage calculation)
512 MB cache per controller (1 GB total)