NetApp Technical Case Study: Using SAN with VMware to Facilitate Storage and Server Consolidation

Many companies are experiencing a rapid proliferation of commodity Intel_ servers. These systems are typically equipped with a small amount of internal or direct-attached disk storage. As server numbers grow into the hundreds, the management complexity for both servers and storage increases exponentially, putting a strain on limited administrator resources and IT budgets.
Server and storage consolidation using VMware ESX software and Network Appliance™ storage systems significantly reduces these problems. VMware allows multiple operating system instances to run on a single physical machine and does not require major changes to existing application software.
Previous VMware implementations have demonstrated that it is possible to reduce the number of deployed Intel-based servers by 50% or more while achieving

- 60% to 80% utilization rates (up from typical rates of <15%)

- Application provisioning time measured in seconds not days

- Response times for change requests measured in minutes

- Zero-downtime hardware maintenance

The benefits of VMware are uniquely complemented by Network Appliance storage solutions. Using NetApp technology, storage can be consolidated onto one or a few storage systems accessed across Fibre Channel SANs or regular IP networks. This dramatically simplifies storage provisioning, increases asset utilization, and allows a company to take advantage of NetApp data protection and disaster recovery functionality. This paper describes the real-world experiences of a customer that reduced its server count 50% and implemented a tapeless storage infrastructure using VMware and NetApp solutions.

Background

In 2001, the company first implemented NetApp storage to support its Oracle® databases. The original F700 series system was upgraded to a F800 series system and then more recently to a FAS960. Today, the FAS960 hosts Oracle via CIFS while providing Fibre Channel SAN storage used by VMware and Microsoft® Exchange servers.
Like many organizations, the company’s Intel-based server environment has grown exponentially over the years to support additional business requirements and applications. At the time, it relied on over 100 servers. After internal benchmark studies against similar companies in the same industry showed that the number of servers was significantly above average for the number of users supported, the company launched an initiative to lower operating costs by reducing servers.
In 2004 the company selected VMware as an enabling technology to replace physical servers with virtual hardware instances running on powerful multiprocessor systems.
VMware requires either direct-attached or SAN-based disk storage. The company chose a Fibre Channel SAN to allow storage to be consolidated onto the existing NetApp storage systems. While building a new Fibre Channel infrastructure can be expensive, the VMware server consolidation project server count was cut dramatically and overall expenditures were significantly reduced. Costs were also offset by the advantages of consolidated storage and the advanced data management capabilities offered by the NetApp platform.

Infrastructure
The company’s SAN infrastructure utilizes two NetApp FAS960 storage systems: one in its main data center and another in a secondary data center. Both FAS960 systems are configured to support SAN-attached VMware servers. An Exchange server in the main data center also utilizes NetApp SAN storage with NetApp SnapManager® for Exchange software. Gigabit Ethernet is deployed throughout each data center. Redundant DS3 circuits link the primary data center to the secondary data center.
Both FAS960 systems have FCP Target cards installed, while all VMware servers are configured with QLogic 2342 adapters. Exchange 2003 hosts have Emulex initiator cards installed. Servers and storage systems are connected to a Brocade model 3800 fabric switch using factory default settings and no zoning.
Three four-processor Xeon servers have been configured with VMware ESX software. These ESX servers are configured to access LUNs on the NetApp system in the primary data center. An additional four-processor machine is connected to the SAN in the secondary data center and configured in standby mode. VMware SAN volumes and other NetApp volumes are mirrored to the FAS960 in the secondary data center using NetApp SnapMirror® software. In the event of a disaster affecting the primary data center, critical applications running under VMware can be quickly restarted in the secondary location.
LUNs are provisioned in their own qtrees. In accordance with NetApp best practices, each virtualized server is allocated a qtree in a SAN_vmware volume on the NetApp storage system. In addition, each VMware LUN is formatted as a VMFS-2 volume. This allows the VMware Virtual Center to be used to migrate a virtual machine from one VMware ESX host to another while the server is live. This facilitates maintenance or other administrative needs while minimizing application disruptions.