Specifications
Escala Tower PL & S, E, T System Hardware
Chapter 3: External Storage and SAN Subsystems 41/116
9es3s1c3.doc
Rev 5.9
02/12/2003
The dual Storage Control Processor (SP) configuration
offers a higher performance and availability
alternative to the basic configuration through the addition of second SP. The mirrored cache memory
is available as an option. The SPs can be configured to any of the disks within the subsystem,
however,
shared access to a single drive is not supported
. A second DAS 1000, 2000 and 3000 Series array can
be daisy chained to the first. In the dual SP configuration, system level redundancy is provided at the
drive, power supply and cooling levels. Redundancy at the Storage Control Processor level is also
provided:
failover requires operator interaction with the host system
.
The dual SCSI adapter or Fibre Channel adapter/dual SP configuration
extends the capabilities of
the dual SP configuration by extending a separate SCSI or Fibre bus to the second SP. As with the
previous configurations, the optional cache is available and a second array can be daisy chain to the
first system. Failover of the storage processors, or SCSI-2 adapters, or Fibre Channel adapters can be
initiated
through operator interaction with the host system
.
The cabinet sharing configurations:
in this configuration, the SCSI-2/Fibre Channel-to-SP
connections are on separate SCSI/Fibre buses, thereby allowing both host systems to share the DAS
array as a highly integrated, high availability storage solution.
Limitations to the DAS 1000, 2000 and 3000 Series Cabinet Sharing Configuration:
•
Dynamically shared access by two systems to a single drive requires host software (HACMP).
•
HACMP configurations are supported on redundant configurations.
3.14. Configuration Rules and Hints for the DAS1300, DAS2900 and DAS3200/DAS3500
3.14.1. Basic Cabinet
One SP is included in the basic cabinet, with 3 power modules for DAS2900 or DAS3200/DAS3500,
only 1 for DAS1300.
3.14.2. Number of Disk Drives Allowed
DAS3200/DAS3500: 5 to 30
DAS2900: 5 to 20
DAS1300 without cache: 3 to 10
DAS1300 with cache: 5 to 10
All models with cache and hot-spare disk 6 to 10, 20 or 30
A location exclusion exists between the hot-spare disks and the 5-disk group dedicated to cache
saving.