PCI SSA-RAID (Cluster) Adapter

For IBM SSA RAID Cluster Adapter see >   Installation and User's Guide



The IBM PCI SSA-RAID Controller

The adapter has four external connectors (two pairs of SSA connectors).
Connectors A1 and A2 are always paired off together and Connectors B1 and B2 are always paired off together.

The Loop Control LED (located next to each pair of loop connectors.)

Before start repair actions - verify

See TIP > NF 5500 and NF 5500-M10 Use of SSA Adapter
See TIP > STOP SSA Event Logger before HOST Software installation
See TIP > SSA RAID Adapter restricted to RAID 5 with OVER 2GB of RAM
See TIP > Failover issues: SSA Cluster Adapter and Host SW 1.06, 1.07

If the system cannot work with the PCI-SSA adapter,
check the following:

If the system cannot access the SSA disk drives,
check the following:

If the system fails to boot from an SSA disk drive,
check the following:

See > IBM SSA RAID (Cluster) Adapter   Installation and User's Guide

                                    FRU P/N   OPT P/N   MFG P/N
 IBM PCI SSA-RAID Adapter           32H3811   32H3811
 IBM SSA-RAID Cluster Adapter       02L7644   96H9835   96H9848
     - " -    Memory (SIMM 16MB)    76H5657   89H5651
 ---- 3527 SSA-Options -------------------------------
  1.0 m SSA external cable pair               59H7220
  2.5 m SSA external cable pair               59H7221
  5.0 m SSA external cable pair               59H7222
 10.0 m SSA external cable pair               59H7223
 25.0 m SSA external cable pair               59H7224
 SSA  Dummy Disk Drive Module                 05J6411
 Two external SSA-cables are packaged with each P/N.
 This allows the SSA loop to be implemented.
 The 3527 can support a max. of five SSA hot-swap disk drives. If less
 than five disk drives are used, SSA dummy disk drive modules must be
 inserted into the empty bays to maintain continuity of the SSA loop.

SSA RAID Adapter Supported Servers

Server Max. Number
PC Server 320
1 19A
PC Server 320
1 M54PE-16T3B
PC Server 325 3 All
PC Server 330 3 All
PC Server 520
1 19A
PC Server 520
1 M54PE-16T3C
PC Server 720 2 11
PC Server 704 3 7

(Oct-1997) Current there is no support for PC Server 310 and 315

See > SSA RAID Adapter restricted to RAID-5 with over 2GB of Memory

Note: The maximum number of adapter supported is based on how many full-sized PCI adapters will physically fit in each server and what number have been officially tested by IBM. Larger numbers than those listed may function correctly, but may not be supported.


The IBM SSA RAID Adapter is a PCI bus master adapter that serves as the interface between systems using the Peripheral Component Interconnect (PCI) architecture and devices using the Serial Storage Architecture (SSA). The adapter provides high performance implementation of RAID-0, RAID-1 and RAID-5. It can also provide storage in a non-RAID configuration if required, for maximum storage space.

The SSA RAID Adapter supports the following operating systems:

Note 1 Device drivers for all these network operating systems (NOEs) are supplied with the adapter.

The configuration utility allows you to configure and administer the SSA configuration online from within the operating system. There is also a DOS-based configuration that allows to configure SSA configurations offline. (There is no DOS device driver available !)

To install the SSA RAID Configurator and Utilities on a system already running DOS, perform the following steps:
  1.  Insert the SSA RAID DOS Configurator and Utilities diskette in the diskette drive
  2.  Press Ctrl+Alt+Del to reboot the system
  3.  Verify the time and date or just press Enter twice to bypass them.  At the DOS prompt type:


     Then press Enter.


SAA is an open ANSI standard, X3T10.1. At the moment the maximum transfer rate is 80MBps (4-ports x 20MBps).

SSA Characteristics

Components on SSA loops are called nodes, a node can be either an Initiator or a Target. An initiator issues commands, and targets respond with data and status.
The SSA nodes in the adapter are therefore initiators and the SSA nodes in the disk drives are targets.
Each SSA node is given a unique address (UID) at the time of its manufacture, which allows the initiators in the loop to determine what other SSA nodes are attached to the loop.

The SSA architecture allows more than one initiator to be present in a loop. In that case, commands and data from multiple initiators can be directed to the same or different targets and intermixed freely. Error recording in an SSA network is coordinated by one particular initiator, known as the master initiator. This is the initiator with the highest UID. If a new initiator is added to the network with a higher UID than those currently present, it takes over the master responsibilities for that network.
Similary, if a master initiator is removed from the SSA network, the initiator with the next higher UID takes over master responsibility. This master handover occurs autom. w/o any user intervention.

The master initiator has two primary functions:

  1.  The node where all asynchronous alerts  are sent
  2.  Coordinator of error recovery procedures

Asynchronous alerts are used to notify the master initiator asynchronously of high-severity errors or conditions.

The basic unit of data transferred between SSA nodes in a frame which contains 1 byte describing the frame type, 4 bytes of CRC, up to 6 bytes of addressing and up to 128 bytes of data. The data block contains either an SSA message or the user data.

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