The following document focuses on the setup of a SAN (Storage Area Network) system — IBM
® DS3400. The document also describes an example environment of multiple Telephony Application Server systems with a single standby/failover server. A SAN is a hard requirement for this environment.
- FC: Fiber Channel: A gigabit speed network technology used to access storage networking. Can be either twisted pair or fiber-optic
- SAN: Storage Area Network. A disk array that is accessed with an FC
- HBA: Host Bus Adapter. The PCI card installed in the host to access the SAN or SAN switch with an FC
- Array: Set of disk drives logically grouped and associated to a RAID level
- Logical Drive: Virtual component created for the host to access an allocated portion of the disk array
- LUN: Logical Unit Number. The logical drive identifier as it is known to the accessing host
The hardware components relevant to this setup focus on the Telephony Application Server and SAN portion of the topology, with no details of the Sametime
® Server or Telephony Control Server. These components remain unchanged and are independent of a Telephony Application Server and SAN. The following table includes the hardware components and reference host names for examples used through the document.
|Component ||Type/Model|| Type/Model |
|TAS_1||IBM xSeries® 3550 M3||stx3455d |
|TAS_2 ||IBM xSeries 3550 M3||stx3455e|
|TAS_3 IBM ||xSeries 3550 M3 ||stx3455f |
|TAS_4 IBM ||xSeries 3550 M3 ||stx3455g |
|TAS_5 IBM ||xSeries 3550 M3 ||stx3455h |
|SAN Disk System ||IBM DS3400 ||N/A|
|24 Port SAN Switch ||IBM SAN 24B-4 ||N/A|
The following diagram details the overall architecture of IBM Sametime
Unified Telephony in a failover environment. HBA cards are installed on all Telephony Application Server systems, including the standby systems. The Telephony Application Server systems are then in a position to connect to the SAN with a SAN switch.
The cluster software, SAMP, is not included in this diagram. Full deployment descriptions, including how the cluster software interacts with the topology, are provided in subsequent sections. The main purpose of this section is to explain how the SAN is used.
Configuring SAN LUNs:
The following diagram provides an example logical mapping of hosts/partitionsto SAN LUNs. The SAN is broken up into logical disk arrays which the HBA (host bus adapter) cards on the Telephony Application Server servers access with standard SATA drive mappings, for example, sda and sdb. The table provides an example host-to-LUN mapping, along with their associated array allocations. For example, the Telephony Application Server residing on host stx3455b mounts the /enterprise
directory with the SATA drive sdb, which maps to LUN 0
on the SAN.
The active and standby Telephony Application Server systems interact with the SAN LUNs in the following manner:
By providing the logical mappings to each system, the standby can take over from any system in the cluster.
All systems maintain all logical mappings. If the standby takes over from a failed system, once the failed system has been repaired, for example with an operating system patch, the original active node becomes the acting standby node.
The SAN is configured using a utility called Storage Manager — a simple interface for configuring arrays and logical drives. Use the Storage Manager utility to create new logical drives, name logical drives, and view the logical drive name to LUN mapping. For simplicity, the SAN can be configured with a host group that contains all Telephony Application Servers, enabling all Telephony Application Servers access to all LUNs. With this configuration, mount the appropriate LUN from the appropriate machine. The diagram provides an example array allocation, including the relevant Host Group:
Parent topic: Setting up hardware for a Storage Area Network