Avago Technologies 3ware SAS 9750-16i4e - Manual (Page 188)

Chapter 9. Maintaining Your Controller
176 3ware SATA+SAS RAID Controller Card Software User Guide, Version 10.2
Viewing Battery Information
The Battery Backup Unit (BBU) is an add-on card that can be attached to
3ware 9750 RAID controllers to supply power from a battery pack in the
event of a system power loss. This allows the controller to use write-caching
for optimal performance and to preserve data in the event of a system power
failure. When fully charged, the battery preserves the contents of the cache
memory for up to 72 hours. When power is restored, the cached write data is
written to the disks.
You can see information about a battery backup unit attached to your
controller in both 3DM2 and 3BM.
To view information about a BBU in 3DM2
• On the menu bar, choose Monitor >> Battery Backup.
The Battery Backup page appears, on which you can see details and status
about the unit. This page is refreshed every 30 seconds.
For details about the fields on this page, see “Battery Backup page” on
page 218.
To view information about a BBU in 3BM
• At the main 3BM screen, tab to the Information button and press Enter.
On the pop-up menu, select Battery Backup and press Enter.
The Battery Backup Unit screen appears.
The fields on this screen are the same as those available through 3DM2.
For details about the fields, see “Battery Backup page” on page 218.
Testing Battery Capacity
Batteries in the BBU need to be replaced periodically. A battery test should be
run every four weeks in order to get a reliable estimate of battery capacity, and
to determine when it needs to be replaced.
The battery test is used to measure the battery’s capacity to back up write data.
In order to make a reliable estimate of battery capacity, the BBU pre-charges
Mac User Note: Disregard the sentence directly above, and use “You can see
information about a battery backup unit attached to your controller in
3DM2.”
Note: When the BBU status is not “Ready,” write caching is automatically disabled
on all units attached to the controller