Brocade HBA - Stream I/O Performance
To alleviate the friction between business processes and IT infrastructure inflexibility savvy CIOs are utilizing virtual machines (VMs) in a Virtual Operating Environments (VOE), such as that created by VMware to provide the reliability, availability and scalability of racks of servers, while reducing capital and operating expenses. Nonetheless, the road to nirvana has its complications. Virtualization dramatically increases I/O loads on servers and the expansion of government regulations on risk management highlights the danger that the failure of a single host server will cascade to multiple VMs running multiple applications. In this white paper, VSM Labs explicitly focused on the server I/O problems associated with the implementation of an end-to-end backup and recovery process within a VOE.
With servers hosting eight or more VMs, an FC HBA can no longer be regarded as a simple commodity product. As the number of VMs sharing the HBAs in a host server increases, SAN fan-out becomes a server issue as well as a switch issue. In a VOE server, HBAs have to play the role of virtual switches for virtual fabrics created by virtual HBAs assigned via N_Port ID virtualization. To deal with this issue, Brocade HBAs employ a high-performance ASIC that supports 500,000 IOPS per port and incorporates an 8-lane Gen 2.0 PCIe interface for 40 Gbit/sec internal server throughput. This level of performance is particularly important for supporting the high level SAN I/O throughput needed by end-to-end backup and recovery processes in a VOE.
To optimize resource utilization, sites typically run eight or more VMs on host servers that utilize multi-core processors. Dense VM configurations put significant stress on I/O throughput for host servers, which must virtualize all of the SAN hardware for multiple VMs.
A major issue for VOE backup is the significant I/O overhead incurred in a process that utilizes VMware Consolidated Backup (VCB). In a VCB-based backup, all data must be read and written twice: once to a local directory on a server dubbed the VCB proxy server, and then again to the backup media. With data being simultaneously read and written in both phases of a VCB-based backup, achieving optimal efficiency requires a VCB proxy server that can provide a very high level of I/O throughput.
What's more, VCB can move all data over a SAN using just the HBAs installed in the VCB proxy server. That puts a premium on the ability to reach high I/O throughput levels without the need for manual tuning and intervention by system and storage administrators. With operating costs dominating capital costs for storage resources, any solution that requires significant manual configuration or tuning efforts cannot be cost effective. Within that context, VSM Labs examined the Brocade 815 and 825 HBAs, which are also available directly through HP as the HP 82B PCIe single and dual port HBAs.
To provide a baseline for our VOE backup testing, we first installed three single-port 8-Gbit/sec HBAs, a Brocade 815, a QLogic QLE2560, and an Emulex LPe12000 on a quad-core HP ProLiant DL360 server running Windows Server 2003 and the Intel Iometer benchmark. This server would later assume the role of our VCB proxy server. At the center of our 8-Gbit/sec test fabric, we configured a Brocade 300 switch.
To provide a complete VOE test environment, openBench Labs utilized three servers, along with a SEPATON S2100-ES2 virtual tape library (VTL) with two 4-Gbit/sec FC ports, and a Xiotech® Emprise 5000 storage system also having two 4-Gbit/sec FC ports. We hosted eight VMs running Windows Server 2003 on a quad-processor HP ProLiant DL580 server running VMware ESX Server 3.5 and managed our VOE from an HP ProLiant DL360 server running VMware vCenter Server (a.k.a. Virtual Center) on Windows Server 2003.