1Bbu Cache Enable Mode; 1Cnt (Controller) Cache Enable Mode; Access Control Features - NEC S1300 User Manual

1BBU Cache Enable Mode

1CNT (Controller) Cache Enable Mode

Access Control Features

Objective of Access Control
About Access Control
Modes Supported by Access Control
This Manual:http://www.manuallib.com/nec/s1300ug-disk-array-unit-user-guide.html
Normally your DAU includes two battery backup units to retain write data in the cache
memory of each controller in the event of a system shutdown or power failure. When
only one battery backup unit is in service, the DAU is not redundant and data loss may
occur if this battery unit fails. For this reason, it is recommended that 1BBU cache
enable mode be turned off when only one battery backup unit is in use.
OFF state: The write cache is disabled in the single-BBU condition.
ON state: The write cache is enabled even in the single-BBU condition. (Shipping default)
Normally your DAU includes two controllers, each containing cache memory to retain
write data in the event of a system shutdown or power failure. When only one controller
is in service, the DAU is not redundant and lost data may occur if the cache in this
controller is enabled and this controller fails. For this reason, it is recommended that
1CNT cache enable mode be turned off when only one controller is in use.
OFF state: The write cache is disabled in the single-controller condition. (Shipping default)
ON state: The write cache is enabled even in the single-controller condition.
Access control allows logical disks in a DAU the ability to establish port and host
access permissions. Access control also provides a logical disk masking feature on a
port-by-port or host-by-host basis to protect the data and ensure the security.
To achieve the above objectives, the access control determines those logical disks
accessible from the controller or host and masks these disks. When you want to use the
access control, the cross call feature must be turned on.
The access control feature supports the following two modes.
!
Port mode
!
WWN mode
Disk Array Unit Overview 1-9