Linux is well known for high-availability clustering, which conjures up an image of racks of server clusters. Embedded Linux installations also often require a tighter integration with hot-swap hardware, including hot-swappable processor boards (see the figure). But satisfying both requirements, high availability and hot swapping, isn't a trivial task. Monta Vista believes it has the answer in its High Availability Framework, built on the company's Hard Hat Linux.
This framework consists of a number of components, including:
- CompactPCI hot-swap support implemented to the PICMG 2.12 standard
- Active/backup Ethernet support
- Hot-swap-aware Ethernet drivers
- Disk mirroring (RAID 1) with boot support on x86 architectures
- Real-time kernel resource monitoring architecture
- Publish-subscribe event architecture
- Hot-swap-aware Hard Hat Net
- Intelligent Platform Management Interface (IPMI) support.
PICMG 2.12 support lets the Framework operate with a large number of standard CompactPCI chassis, processors, and adapters. Active/backup Ethernet support allows transparent failure with a dual adapter configuration. Software-based RAID 1 support works with all Hard Hat Linux platforms with an enhanced version of lilo, the boot loader, for the x86 architectures.
Its publish-subscribe architecture allows applications to be spread across multiple systems. Applications can be notified of changes to information in a standard fashion. Hard Hat Net supports this architecture by permitting a CompactPCI system to emulate an Ethernet network. Hard Hat Net is now hot-swap-aware.
The framework supports the open-source IPMI. IPMI provides remote monitoring capabilities for a range of system indicators, such as power levels, temperature, and memory errors. Also, the framework supports several PowerPC and Intel CPUs. PowerPC architectures supported include 74xx, 7xx, 82xx, and 8xx.
More information about the framework can be found at www.mvista.com.