Updating Fibre Channel Drivers to Use Sun StorEdge SAN Foundation Software

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Here are some reasons to upgrade to the Leadville Fibre Channel (FC) stack. (Leadville is the code name for Sun StorEdge SAN Foundation Software, previously known as Sun StorageTek SAN Foundation Software.)

In the past few years, the amount of data stored throughout the world has been increasing at an incredible speed. Fibre Channel has come to dominate the high-end enterprise market, because FC-SAN has higher levels of availability, performance, and reliability than IP-SAN and other storage solutions.

Enterprise applications are relying on FC more than ever, but most operating systems still recognize FC devices as parallel SCSI devices through driver emulation. Although this approach has met initial customers' needs, enterprise SANs are growing in scale, complexity, and importance, which means that traditional SCSI devices can no longer satisfy these performance-sensitive and large-scale applications. And, because of the multi-vendor nature of enterprise SANs, quality assurance, end-to-end testing, and technical support have become the major challenges for customers using drivers that present FC devices and LUNs as SCSI devices.

To better meet the need of customers, Sun developed the Leadville FC stack from scratch to supersede the traditional SCSI emulation method.

Leadville is the code name for the StorEdge SAN Foundation Software (SFS), which Sun developed for the Solaris Operating System (OS). Leadville is a new, open standards-based I/O framework and device driver stack to support FC. Since the Solaris 10 release, Leadville has been fully integrated into the OS, making it even easier for system administrators to use. This stack is available on SPARC, x64, and x86 platforms. In addition, because the Leadville stack is integrated into the operating system, it is part of all the Solaris update releases, enabling continuous innovation and predictable quality.

The following diagram depicts an overview of the Leadville FC stack in the Solaris OS.

Figure 1: Sun StorEdge SAN Foundation (Leadville) FC Stack

The Leadville FC stack is fully integrated into the Solaris OS for high performance, and it provides a means of extending the stack to support new features of the FC and Storage Networking Industry Association (SNIA) standards as they evolve. The layers that make up the stack are described below:

1. Vendor Drivers. The Leadville framework provides a well-defined interface to enable Host Bus Adapter (HBA) vendors to quickly support new cards and FC technology.

2. FC Protocol Layer. At the heart of the Leadville I/O stack is the Fibre Channel Protocol (FCP) layer, which is a common Sun component acting as an interface to provide consistent behavior for how systems running the Solaris OS attach to a SAN. The FC Protocol layer provides a rich interface to the FC HBAs (FCAs) and reduces the complexity of SANs by utilizing well-known interfaces into the core of the Solaris OS. This layer consists of Upper Layer Protocols (ULPs), a transport module, and FCAs. Leadville now supports these ULPs: FCP, IP over Fibre Channel (FCIP), and SunFC SAN Management (FCSM). And, every FCA corresponds with one Fibre Channel Port (FP) instance.

   It is important to note that Leadville is a part of the native Solaris OS. No patches are required to integrate with other features of the Solaris 10 OS, such as Solaris ZFS, Solaris Containers, Sun Cluster software, and disaster recovery. Because the stack is integrated into the operating system, it benefits from the intensive testing process that the Solaris OS undergoes before every release and across all products.

3. Multiplexed I/O (MPxIO). MPxIO is the multipathing driver (scsi_vhci) within the Solaris OS.

4. Target drivers. All Solaris target drivers are supported by the Leadville stack.

5. Management Interfaces. Leadville provides open, standard interfaces to administer SAN storage. The Multipath Management API (MMA) and FC HBA API have been integrated into the Solaris OS.

Although the nature of the physical storage interconnects changed from SCSI to FC, the device drivers for early FC HBAs are written to the old SCSI driver frameworks. So, in most non-Solaris OSs, such as Linux or FreeBSD, FC configuration still appears as a DAS SCSI configuration. Furthermore, some third-party vendors still support their FC HBAs like SCSI HBAs in the Solaris OS. This method of using FC can lead to more and more problems.

The Leadville FC stack has some significant advantages over the traditional SCSI emulation drivers, and Leadville provides critical new capabilities for customers linking their servers running the Solaris OS to SANs. These capabilities include:

• Dynamic addition of new devices. Leadville supports automatically adding, upgrading, and replacing storage devices without rebooting the servers. This reconfiguration will not influence applications.
• Persistent binding. This can avoid manually binding the SCSI device name to the World Wide Name. Leadville allows the operating system to see FC devices directly. This also reduces the time and effort required to upgrade and maintain storage devices.
• Virtually limitless scalability. The number of physical devices that can be attached to every FC port is not limited as with SCSI ports. Leadville can potentially see millions of devices on the fabric, providing the ability to scale the fabric to meet virtually any business requirement.
• Support for multipathing. The multipathing capability (MPxIO) provides significantly higher performance for I/O intensive applications. Both Leadville and MPxIO are seamlessly integrated into the Solaris OS.
• Common driver set for HBAs. This helps reduce complexity and management tasks by eliminating the need to buy, install, and track firmware and patches for each HBA and array.
• Better I/O stack. Since Sun develops the operating system for its servers, Sun is in the ideal position to develop a better I/O connection, or stack, into its servers. In essence, Sun is providing a clean, well standardized, open interface point at the SAN port on Sun servers with single-vendor accountability, reduced complexity, and simplified support for customers.

The Solaris 10 release is bundled with the Leadville FC drivers, so after you install the Solaris 10 OS, you can start to enjoy the advantages of Leadville.

If you are using the Solaris 9 or Solaris 8 releases, you can download and install the latest SFS package (Leadville) from the SAN engineering site, as follows:

1. Point your browser at the SAN engineering site:
   http://www.sun.com/storagetek/storage_networking/
2. Click on the link for SAN 4.4 release Software/Firmware Upgrades & Documentation.
3. Download the archive SAN_4.4.x_install_it.tar.Z
4. Copy the archive to the system to be installed.
5. Unpack the archive:

# zcat SAN_4.4.x_install_it.tar.Z | tar xvf -



6. As root, run the following commands:

# cd SAN_4.4.x_install_it # ./install_it



7. Reboot the system.

If you have been using third-party FC drivers in the Solaris OS, you can upgrade your system to use Leadville:

1. Remove the third-party drivers. For example:
• # pkgrm QLA2300 (to remove QLogic native drivers)
• # pkgrm lpfc (to remove Emulex native drivers)
2. For the Solaris 10 OS, modify the /etc/driver_alias file to un-comment all lines starting with qlc and emlxs. For example:
   • emlxs "pci10df,f900"
   • qlc "pci1077,2312"
3. For Solaris 8 or Solaris 9 OS, use the installation procedure described above to install the Leadville FC drivers.
4. When necessary, update the /etc/vfstab file to reflect the disk name changes.
   When using Leadville, the disk name will look like /dev/dsk/c6t20000011C6E60AECd0 in non-mpxio mode or /dev/dsk/c6t600C0FF0000000000A7AFE58D3286000d0 in mpxio mode.
5. If you are booting from the FC disks, refer to the Solaris lpfc to emlxs (SFS) Migration Guide (pdf) for more required changes.
6. Reboot the system.

• OpenSolaris Community: Storage
• Solaris Fibre Channel and Storage Multipathing Administration Guide, 819-0139-10 (on docs.sun.com)
• The Sun I/O Stack and its Benefits for EMC Storage (pdf)
• Solaris lpfc to emlxs (SFS) Migration Guide (pdf)
• T10 Technical Committee
• T11 Technical Committee