LSI MegaRAID LSIiBBU08 Intelligent Battery Backup Unit

MX36789 MegaRAID LSIiBBU08 Intelligent Battery Backup Unit
MX36789 MegaRAID LSIiBBU08 Intelligent Battery Backup Unit MX36789 MegaRAID LSIiBBU08 Intelligent Battery Backup Unit MX36789 MegaRAID LSIiBBU08 Intelligent Battery Backup Unit MX36789 MegaRAID LSIiBBU08 Intelligent Battery Backup Unit

Product Info

Intelligent Battery Backup Unit for 6Gb/s MegaRAID SAS Controller Cards

LSI battery backup units are add-on modules that protect against data loss in the event of a server or power failure by providing emergency power to the cache memory. When power is restored, the data not yet written to the hard drives can be retrieved from cache memory.

LSI provides a family of intelligent battery backup units (iBBUs) for use with its high-performance RAID controllers. The LSI iBBUs provide an inexpensive alternative to using an uninterruptible power supply (UPS) and a second level of fault tolerance when used in conjunction with a UPS.

The LSIiBBU08, used with the MegaRAID SAS 9260 and 9280 series controllers, provides higher ambient temperature tolerances and increased serviceability while protecting the integrity of cached data in the event of a power or server failure.


  • Helps protects integrity of cache in the event of power or server failure
  • Higher maximum ambient temperature tolerance than previous generation battery backup units
  • Multiple modes of operation and retention times
  • Transparent and shorter learning cycles
  • For use on all existing 6Gb/s MegaRAID controllers
  • Customize mounting location in chassis with remote mounting options

Higher Ambient Temperature Tolerances and Increase Serviceability

The LSIiBBU08 can tolerate higher ambient temperatures around the battery backup unit as compared to the previous generation battery, with tolerances of up to 55°C versus 45°C for ambient cell temperature. There is also a remote mount option available which allows customers who have limited chassis space or a constrained thermal environment to reposition the battery backup unit away from the RAID controller card for cooling purposes. A lower temperature environment will generally help prolong the service life of a battery backup unit, while high temperatures and extreme conditions will shorten the battery life. For example, if the battery is set to a 12-hour DRT and 45°C mode, it may not require replacement for the life of the RAID controller1. However, using a 48-hour DRT and 55°C mode with your battery may cause a situation where the battery requires replacement after the first year of use2.

Multiple Modes of Operation and Retention Time

The LSIiBBU08 allows for multiple modes of operation, which let the user select a shut-off data retention time (DRT) of 12, 24, or 48 hours with as - sociated operating temperatures, learn cycles, and estimated service lives. The MegaRAID controller firmware will use the LSIiBBU08 until it calculates that the battery can only guarantee cache data for the selected period of time in the event of power loss to the server. With previous generation MegaRAID batteries, there was only one mode of operation with a retention time of 72 hours. By offering these multiple modes of operation, the LSIiBBU08 provides the flexibility to select the optimum DRT, performance based on cache policy, and maximum operating temperature that best fits their specific application and environment.

LSIiBBU08 Mode 1 Mode 2 Mode 3 Mode 4 Mode 5
Data Retention Time (DRT) 2 12 Hrs 12 Hrs 12 Hrs 48 Hrs 48 Hrs
Transparent Learn Cycle Yes Yes Yes No No
Op Temp (Charging Temp) 45°C 55°C 45°C 45°C 55°C
Estimated service life3 5 Years 3 Years 3 Years 3 Years 1 Year

Transparent and Shorter Learn Cycles

The battery learn cycle is the process where MegaRAID firmware recalibrates the bat - tery gas gauge with respect to the battery's chemical capacity so that controller can decide whether or not the battery can maintain the controller cache for the selected period of time (DRT) in the event of a power failure. The battery learn cycle partially discharges and then fully charges the battery backup unit.

With the LSIiBBU08, if the user requests a limited DRT of 12 or 24 hours, the controller will continue to work in write-back mode during the discharge and recharge learn cy - cle. In the event of a power failure during this learn cycle, the controller is designed to accommodate that there is still enough energy left in the battery to provide the selected retention time (12 or 24 hours). Because the learn cycles can be performed as needed by the BBU without impact to the write cache policy or performance, this is called a transparent learn cycle.

During the learn cycle in 48-hour DRT modes, the controller is forced to a write- through cache policy for the duration of the discharge/recharge process, as the Relative State of Charge crosses the boundary where the stated retention time can - not be maintained. This cache policy writes the data directly to the disk and helps protect against data loss during a potential power loss. While this is similar to the existing learn cycle process for the LSIiBBU07 with a 72 hour DRT, it does allow for much shorter learn cycles. Typically, the LSIiBBU08 only takes 3-4 hours to discharge and recharge the battery to capacity, versus an 8-10 hour process required with the LSIiBBU07 due to periodic deep discharges.


Mode 1: The LSIiBBU08 uses a small board-to-board connector to mount directly to the following SAS RAID controllers:

  • MegaRAID SAS 9260-4i
  • MegaRAID SAS 9260-8i
  • MegaRAID SAS 9261-8i
  • MegaRAID SAS 9280-4i4e
  • MegaRAID SAS 9280-8e

Mode 2: The LSIiBBU08 connects remotely to the following SAS RAID controllers using a 12-inch cable or, where applicable (*), a 12-inch cable and a remote interposer board that are sold separately in a Remote Battery Kit:

  • MegaRAID SAS 9260-4i*
  • MegaRAID SAS 9260-8i*
  • MegaRAID SAS 9260-16i
  • MegaRAID SAS 9261-8i
  • MegaRAID SAS 9280-4i4e
  • MegaRAID SAS 9280-8e
  • MegaRAID SAS 9280-16i4e
  • MegaRAID SAS 9280-24i4e

Package Contents

  • 1 x LSIiBBU08 Battery Backup Unit
  • 1 x Remote Cable