Apple Xserve RAID: Using RAID 1.2 Admin and Disk Utility User Manual
Page 31
Chapter 3
Monitoring Status and Changing Settings
31
To adjust fibre channel settings for a host computer:
1
Open Fibre Channel Utility on the host computer for which you want to adjust settings.
2
Click the lock icon, enter the admin password for the system, and click OK.
3
Select the port for which you want to adjust speed or topology.
4
Choose a speed or topology setting from the appropriate pop-up menu.
5
Select Enable Hard Loop ID if you must assign a fixed address on your fibre channel
loop. Check with your network administrator if you need more information about this
setting.
6
Click Apply.
7
Click the lock icon to prevent further changes.
Note: You must restart the host computer for the change in fibre channel settings to
take effect.
Setting Up Drive Cache and Controller Cache
RAID Admin lets you turn on two separate types of cache to enhance performance of
your Xserve RAID system.
•
Drive cache enables the built-in write cache on each drive in the array. This option
improves efficiency and speed of data transfer, but the drive cache is not backed up
should the system lose power unless you are using an uninterruptible power supply
(UPS).
Important:
It is recommended that you use a UPS when you have drive cache
enabled. Without UPS backup, you could lose data in the drive cache in the event of
a power failure.
•
Controller cache is a write cache used by the RAID controller. This cache is backed up
by the optional Xserve RAID Cache Backup Battery Modules.
Important:
It is recommended that you have the optional controller cache backup
battery modules installed if you use controller cache. Using controller cache with no
battery backup could result in data loss in the controller cache if there is a power
failure.
Note: Using a UPS and cache backup battery modules lessens the potential for data
loss, but these safeguards are not a guarantee against data loss. See your system
administrator or other expert for advice on preventing data loss.