HP StorageWorks HSG60 and HSG80 Array Controller and Array Controller Software Troubleshooting Guide (EK-G80TS-SA. C01, March 2005)

Troubleshooting Information
47HSG60 and HSG80 Array Controller and Array Controller Software Troubleshooting Guide
Note: Disaster-tolerant mirrorsets are not subject to this requirement.
By default, the controller expects to use an ECB as the backup power source for the
supporting cache module. However, if the subsystem is backed up by using a UPS, two
options are available that tell the controller to use the UPS:
■ For BA370 enclosures only, use the ECB and the UPS together with the following
CLI command:
SET controller UPS=NODE_ONLY
■ Use only the UPS as the backup power source with the following CLI command:
SET controller UPS=DATACENTER_WIDE
See the controller CLI reference guide for detailed descriptions of these commands.
Cache policies resulting from cache module failures
If the controller detects a full or partial failure of the supporting cache module or
ECB, the controller automatically reacts to preserve the unwritten data in the
supporting cache module. Depending upon the severity of the failure, the
controller chooses an interim caching technique—also called the cache
policy—until the cache module or ECB is repaired or replaced.
Table 8 shows the cache policies resulting from a full or partial failure of cache
module A (Cache A) in a dual-redundant controller configuration. The
consequences shown in Table 8 are the same for Cache B failures.
Table 9 on page 50 shows the cache policies resulting from a full or partial failure
of the ECB connected to Cache A in a dual-redundant controller configuration.
The consequences shown in Table 9 are the opposite for an ECB failure connected
to Cache B.
■ If the ECB is at least 50% charged, the ECB is still good and is charging.
■ If the ECB is less than 50% charged, the ECB is low but still charging.
Table 8: Cache Policies—Cache Module Status
Cache Module
Status
Cache Policy
Cache A Cache B Unmirrored Cache Mirrored Cache
Good. Good. Data loss: None.
Cache policy: Both controllers
support writeback caching.
Failover: None.
Data loss: None.
Cache policy: Both controllers
support writeback caching.
Failover: None.