Introduction
This guide documents Broadcom® MegaRAID® cache backup products used with MegaRAID SAS high-performance SAS+SATA RAID controllers to protect cached data. These products include:
- CacheVault™ flash module (CVFM) - CVFM04
- CacheVault power modules (CVPMs) - CVPM02, CVPM05
The memory modules protect cached data integrity on MegaRAID controllers by offloading data to nonvolatile flash memory during AC power failures or brief power outages. They offer an alternative to uninterruptible power supplies (UPS) or an additional level of fault tolerance when used with a UPS. This guide details the backup products, installation instructions, and technical specifications.
Cache Backup Benefits
MegaRAID controllers' cache memory significantly improves system performance by enabling faster writes compared to storage devices. Write operations appear complete quickly at the application level, with the controller writing data to storage during low activity or when cache is full. The risk of write-back cache is data loss during an AC power failure before data is written to storage. MegaRAID controllers mitigate this risk with an energy backup solution that offloads cached data to flash memory, which is restored upon power resumption.
CacheVault Modules
CacheVault technology comprises two main components: the CVPM (ultracapacitor-based energy source) and the CVFM (nonvolatile flash memory). The CVPM powers critical adapter components during a power loss, allowing enough time to offload cached data to the CVFM. The CVPM is also known as a supercapacitor or flash backup unit (FBU). CacheVault flash technology reduces hardware maintenance associated with batteries, lowers total cost of ownership, and offers environmentally friendly cache protection while maintaining optimal RAID performance.
The following table outlines cache protection options for MegaRAID adapters:
| MegaRAID Adapter | Adapter Controller | CacheVault Kit | CacheVault Memory Module | Module Information | CacheVault Power Module |
|---|---|---|---|---|---|
| 9560-16i, 9560-8i, 9580-8i8e | SAS3916 or SAS3908 | -- | NAND flash is local on adapter. | The CVPM or supercapacitor provides the CacheVault technology. | CVPM05 (FBU345) |
| 9460-16i, 9460-8i, 9480-8i8e, 9365-28i | SAS3516 or SAS3508 | -- | NAND flash is local on adapter. | Separate flash module not required. | CVPM05 (FBU345) |
| 9361-24i, 9361-16i, 9380-8i8e | SAS3324 or SAS3316 | -- | NAND flash is local on adapter. | CVPM02 (FBU02) | |
| 9361-8i, 9361-4i, 9380-8e, 9380-4i4e | SAS3108 | CVM02 | CVFM04 | Cache protection components are sold as a kit, including the flash module daughter card and the supercapacitor. | CVPM02 |
The modules are described as follows:
- CVPM02 module: A supercapacitor pack mounted remotely or locally, connected by cable to a CVFM or MegaRAID controller.
- CVPM05 module: A supercapacitor pack mounted remotely or locally, connected by cable to a MegaRAID controller.
- CVFM04 module: An ONFI flash module that attaches to a MegaRAID controller and connects via cable to a CVPM02 module on a remote mount board.
ATTENTION: Do not hot plug a CVPM. Hot plugging can damage the board and supercapacitor functionality. Always power down the controller completely before attaching or removing a CVPM.
Installing the Cache Backup Products
This chapter details connecting CacheVault modules for power backup.
CAUTION: Electrostatic discharge (ESD) can damage modules and MegaRAID controllers. Always ground yourself with a strap before touching components. Perform installations at an ESD-safe workstation adhering to EIA-625 and IPC-A-610 standards. Use an ESD-safe Phillips screwdriver for screws, ensuring it is centered to avoid stripping screw heads. Overtightening can damage boards, connectors, or screws, voiding the warranty.
NOTE: To protect data, set the MegaRAID controller Write Policy to write-through until the battery unit is charged. After charging, switch to write-back for improved data caching performance.
Refer to the Handle and Dispose of CacheVault Power Modules section for proper handling and disposal, and CacheVault Module Specifications for technical details. For chassis clipping, see Mount without the Remote Mount Board; for custom clip design, see Using a Custom Mounting Bracket.
Attaching the CVFM04 Module to the MegaRAID Controller and by Cable to a CVPM02 Module on a Remote Mount Board
This section describes attaching the CVFM04 module directly to your MegaRAID controller and connecting it via cable to a CVPM02 module on a BBU-BRACKET-05 remote mount board (sold separately). The CVFM04 attaches to the MegaRAID controller, and the CVPM02 mounts on a clip on the remote mount board. The controller and board are then installed in motherboard PCIe slots. The CVPM02 can also be mounted locally if adequate airflow is maintained.
The CVFM04 and CVPM02 modules are compatible with the following MegaRAID controllers:
- MegaRAID SAS 9361-4i
- MegaRAID SAS 9361-8i
- MegaRAID SAS 9380-4i4e
- MegaRAID SAS 9380-8e
Follow these steps to attach the CVFM04 module directly to your MegaRAID controller and then by cable to the CVPM02 module on a remote mount board:
- Remove the MegaRAID controller from the host system. Refer to Removing the MegaRAID Controller from the Host Computer.
- Attach the CVFM04 module directly to the MegaRAID controller. Refer to Attach the CVFM04 Module Directly to the MegaRAID Controller.
- Install the clip on the remote mount board. Refer to Installing the Clip on the Remote Mount Board.
- Attach the CVPM02 module to the clip. Refer to Attach the CVPM to the Clip on the Remote Mount Board.
- Connect the CVFM04 module to the remote CVPM02 module. Refer to Connect the CVFM04 Module to the Remote CVPM02 Module.
- Install the MegaRAID controller and the remote mounting board in the host computer. Refer to Install the MegaRAID Controller and Remote Mount Board in the Motherboard.
Front View and Back View of the CVFM04 Module
Figure 1 shows the front and back views of the CVFM04 module. The front view is the side visible when the unit is installed on a MegaRAID controller. Record your unit serial number in a safe location for Broadcom support.
Figure 1: Front View and Back View of the CVFM04 Module
Key connectors are:
- J1 - 9-pin Connector to the Remote CVPM02 Module
- J2 - 70-pin Board-to-Board Connector
Removing the MegaRAID Controller from the Host Computer
To remove an installed MegaRAID controller:
- Shut down the host computer, turn off power, and unplug power cords.
- Remove the host computer cover as per the system user manual to access the MegaRAID controller.
- Ground yourself before touching the MegaRAID controller.
- Unplug all cables, remove the bracket screw securing it to the server chassis, and carefully remove the controller from the PCIe slot.
- Place the controller front-side up on a clean, static-free surface for the next procedure.
Attaching the CVFM04 Module Directly to the MegaRAID Controller
Follow these steps to attach the CVFM04 module to the front of the MegaRAID controller:
- Ground yourself and ensure the system is grounded.
- Remove the CVFM04 module from its package.
- Place the CVFM04 module front-side-up on a clean, static-free surface.
- Mount the two standoffs on the controller's front side by screwing them in from the back side. The standoffs thread at both ends.
- NOTE: Center the screwdriver carefully to avoid stripping screw heads. Do not overtighten screws.
- Hold the CVFM04 module with the top side facing upward and align the J2 connector on the CVFM04 module with the connector on the MegaRAID controller.
- Carefully press the CVFM04 module onto the MegaRAID controller until both connectors are firmly joined.
- Secure the CVFM04 module to the MegaRAID controller using two screws from the top side.
Figure 2: Attach the CVFM04 Module Directly to the MegaRAID SAS 9361-8i Controller
Installing the Clip on the Remote Mount Board
Follow these steps to install the clip directly onto the BBU-BRACKET-05 remote mount board:
- Remove the clip and remote mount board module from the package.
- Place the remote mount board on a clean, static-free surface, ground yourself, and ensure the system is grounded.
- Align the clip's screw holes with the screw holes on the remote mount board.
- Secure the clip to the remote mount board using three screws and nuts.
- Thread the screws through the front of the clip and the remote mount board.
- NOTE: Center the screwdriver carefully to avoid stripping screw heads. Do not overtighten screws.
Figure 3: Install the Clip on the Remote Mount Board
Attaching the CVPM to the Clip on the Remote Mount Board
Follow these steps to attach the CVPM to the clip on the remote mount board:
- With the remote mount board on a clean, static-free surface, ground yourself and ensure the system is grounded.
- Remove the CVPM from the package.
- Press the CVPM into the clip on the remote mount board until it clicks firmly into place.
Figure 4: Connect the CVPM to the Clip on the Remote Mount Board
Connecting the CVFM04 Module to the Remote CVPM02 Module
Connect the CVFM04 module on a MegaRAID SAS 9361 controller by cable to the remote CVPM02 module. Use the same steps for other supported MegaRAID controllers:
- Ground yourself and ensure the system is grounded.
- Remove the cable included in the MegaRAID controller box.
- Insert one 9-pin cable connector into the 9-pin J1 connector on the CVFM04 module.
- Insert the other 9-pin cable connector into the 9-pin connector on the remote CVPM02 module, ensuring correct alignment.
Figure 5: Connect the CVFM04 Module on a MegaRAID Controller by Cable to the Remote CVPM02 Module
Installing the MegaRAID Controller and Remote Mount Board in the Motherboard
Install your MegaRAID controller and remote mount board into the motherboard:
- Ensure the chassis power is off, power cords are unplugged, and the chassis is grounded.
- Install the MegaRAID controller into a PCIe slot on the computer. This controller is a PCIe x8 card, compatible with x8 or x16 slots. Note that some PCIe slots are for graphics cards only and may not support controllers. Consult your motherboard guide for PCIe slot compatibility.
- Press down gently but firmly to seat the card correctly in the slot.
- Secure the MegaRAID controller to the server chassis with the bracket screw.
- Insert the remote mount board into a PCIe slot on the motherboard.
- Press down gently but firmly to seat the card correctly in the slot.
- Secure the remote mount board to the server chassis with the bracket screw.
- Replace the computer cover and reattach power cords.
- Turn on the computer power.
Figure 6: Reinstall the MegaRAID Controller
Figure 7: Install the Remote Mount Board
Refer to the 12Gb/s MegaRAID SAS Software User Guide for RAID configuration utility information and the MegaRAID SAS Device Driver Installation User Guide for driver installation details.
Attaching a Remote CVPM05 Module by Cable to a MegaRAID Controller
This section describes attaching the CVPM05 module to a clip on the BBU-BRACKET-05 remote mount board (sold separately) and connecting it via cable to your MegaRAID controller. The MegaRAID controller and remote mount board are installed in motherboard PCIe slots. The CVPM05 can be mounted locally if sufficient airflow is maintained. See CacheVault Module Specifications for airflow requirements.
The CVPM05 module is compatible with the following MegaRAID controllers:
- MegaRAID 9365-28i
- MegaRAID 9460-16i
- MegaRAID 9460-8i
- MegaRAID 9480-8i8e
- MegaRAID 9560-16i
- MegaRAID 9560-8i
- MegaRAID 9580-8i8e
Perform these tasks to attach the CVPM05 module by cable to your MegaRAID controller and install the controller and remote mount board:
- Remove the MegaRAID controller from the host system. Refer to Removing the MegaRAID Controller from the Host Computer.
- Install the clip on the remote mount board. Refer to Installing the Clip on the Remote Mount Board.
- Attach the CVPM05 module to the clip. Refer to Attaching the CVPM to the Clip on the Remote Mount Board.
- Connect the MegaRAID controller by cable to the remote CVPM05 module. Refer to Connect the Remote CVPM05 Module to the MegaRAID Controller.
- Install the MegaRAID controller and the remote mount board in the host computer. Refer to Install the MegaRAID Controller and Remote Mount Board in the Motherboard.
Connecting the Remote CVPM05 Module to the MegaRAID Controller
Follow these steps to connect the remote CVPM05 module by cable to the MegaRAID controller:
- Ground yourself and ensure the system is grounded.
- Remove the cable included in the MegaRAID controller box.
- Insert one 9-pin cable connector into the 9-pin J14 connector on the MegaRAID controller.
- Insert the other 9-pin cable connector into the 9-pin connector on the remote CVPM05 module, ensuring correct alignment.
Figure 8: Connect the Remote CVPM05 Module by Cable to the MegaRAID 9460-16i Controller
Mount without the Remote Mount Board
If mounting the Broadcom retention clip directly to the chassis, ensure no ground path exists to the clip. If attaching the clip to chassis ground, avoid damaging the supercapacitor's outer sleeve during insertion. Damage to the sleeve or contact between the clip and the supercapacitor's metal case can cause failure.
Using a Custom Mounting Bracket
If designing your own retention clip, it must not apply pressure to the top side of the supercapacitor, as this can damage the PCB. Apply retention pressure only to the sides of the supercapacitor. Avoid applying pressure to the top or bottom, as these areas help prevent the supercapacitor from shifting out of the clip.
Figure 9: CVPM Top and Bottom
Refer to CacheVault Module Specifications for supercapacitor dimensions, or download 2D and 3D mechanical drawings from docSAFE at https://portal.broadcom.com/group/support/docsafe (requires login).
Monitor and Manage CacheVault Modules
This chapter explains how to monitor and manage MegaRAID CacheVault modules using Broadcom MegaRAID utility programs:
- Storage Command Line Tool (StorCLI): Command-line management software for the MegaRAID product line.
- Human Interface Infrastructure (HII) configuration utility: A tool for configuring controllers, disks, and performing tasks in a pre-boot UEFI environment.
For more details on CacheVault functions, consult the MegaRAID SAS Software User Guide (for 6Gb/s controllers) or the 12Gb/s MegaRAID SAS Software User Guide (for 12Gb/s controllers).
Monitor CacheVault Module Information in StorCLI
The StorCLI utility supports the following command to identify the controller a CacheVault module is connected to:
storcli /cx/cv show all
The object identifier /cx/cv refers to the CacheVault module on controller x. Only one CacheVault module can connect per controller.
NOTE: This command functions only when a CacheVault module is connected; otherwise, an error message appears.
Input example: storcli /c0/cv show all (where c0 identifies controller number 0).
Monitor CacheVault Module Information with the HII Configuration Utility
Use the HII Configuration utility to display CVPM information on the Battery Management screen. The <SuperCaP> in the Type field refers to the CVPM.
Figure 10: HII Battery Management Screen
Handle and Dispose of CacheVault Power Modules
The CVPM02 and CVPM05 modules are power modules containing individual supercapacitors. These are low-voltage devices capable of delivering extremely high currents, especially in short-circuit situations. Handle supercapacitors in an uncharged state.
General safety considerations:
- Supercapacitors can vent or rupture if overcharged, reverse charged, incinerated, or heated above 150°C.
- Do not crush, mutilate, nail penetrate, or disassemble.
- High case temperature (burn hazard) can result from abuse.
If a capacitor's packaging is compromised (punctured or crushed), a small amount of electrolyte fluid may be released. If a leak is detected (indicated by white salt crystal formation), remove the product from the system. A leaking capacitor can increase resistance or cause long-term corrosion of interconnects. Incidental contact with the white salt residue is not harmful, but it should not be ingested. Take normal precautions after contact, including washing hands.
Supercapacitors are composed of aluminum, carbon, paper, and an organic electrolyte, containing no heavy metals or toxic materials. Disposal regulations vary by municipality. A material safety data sheet (MSDS) for the electrolyte (acetonitrile) is available to assist with regional or local classification and disposal requirements.
CacheVault Module Specifications
The following table lists specifications for the CVFM and CVPMs. Ensure your system's airflow allows the CacheVault device to operate within the specified temperature range.
| Specification | CacheVault Flash Module 04 | CacheVault Power Module 02, CacheVault Power Module 05 |
|---|---|---|
| Technology | On-board ONFI flash module | Remote supercapacitor pack |
| Operating temperature (ambient) | 0°C to 55°C | |
| Storage temperature | -40°C to 70°C | |
| Humidity (storage and operating) | 5% to 95% noncondensing | |
| Mechanical (form factor) | 2.087 in. x 1.378 in. | See Figure 11, CVPM Dimensions. |
Figure 11 shows the CVPM02 and CVPM05 module form factor information.
Figure 11: CVPM Dimensions
Revision History
- Version 1.1; June 8, 2021: Added Mount without the Remote Mount Board and Using a Custom Mounting Bracket. Template update.
- Version 1.0; February 14, 2020: Initial release, based on the Cache Backup Products for MegaRAID SAS+SATA RAID Controllers User Guide (document number CacheVault-05-UG).
