iSCSI SAN Storage:
Growth challenges in Microsoft Exchange environments can be solved with the deployment of iSCSI storage. Microsoft favors block storage such as iSCSI for Exchange deployments. Attaching iSCSI storage to a network provides the server with headroom for adding Exchange users, since the iSCSI SAN Storage can grow without being restrained by the server's ability to add storage.
The key to any high performance iSCSI SAN Storage configuration in an Exchange environment is ensuring the servers using iSCSI and the iSCSI storage run at speeds sufficient to allow fast Exchange mailbox store access. Along with performance, the Exchange configuration must responsibly balance the E-mail load between the client systems, servers and iSCSI storage.
This paper will examine the benefits of using iSCSI storage in an Exchange environment. Specific deployment scenarios using Alacritech and Network Appliance iSCSI equipment will be described, including growing Exchange storage, protecting the Exchange database with snapshot services, and adding resiliency to an Exchange deployment.
Expanding Corporate IT Demand for E-mail iSCSI SAN Storage:
The expanding use of E-mail throughout companies has raised the bar for IT managers, requiring them to not only provide global mail availability and fast response times to their users but to also backup mail communications for archival and regulatory compliance purposes. These requirements have substantially increased the iSCSI SAN Storage needs for companies and subsequently increased the support burden throughout the data center infrastructure. The ripple effect extends from the increased storage bandwidth requirements through to the server processing power that handles all mail delivery, backups, and other critical IT functions.
iSCSI SAN Storage Solutions:
Servers running Microsoft Exchange face a deluge of data in this high growth environment. Beyond standard E-mail delivery, additional requirements are pushed into the storage and server infrastructures, including backing up mailbox stores, providing failover during network outages and guaranteeing fast delivery of data to users. This set of requirements can overwhelm even the most experienced IT group, especially when faced with growing storage requirements, multiple network configurations and highly complex software management packages.
Given a modest 5% increase in IT spending levels worldwide, many corporations are looking at newer, more affordable ways of managing larger and more complex E-mail infrastructures. The best possible scenario would be to leverage existing assets while also providing a scalable solution for storage, networking and servers. One answer to this dilemma is to merge both storage and networking technology investments to maximize spending resources. While disparate strategies from storage and network companies have led to duplicated storage fabrics running alongside network switches and gateways in IT departments, new storage protocols that utilize existing network connectivity can provide expansion opportunities for E-mail storage growth and at cost levels more in line with existing budget constraints.
Growth Challenges in Microsoft Exchange Environments (iSCSI SAN Storage Solution)
In a typical small to medium business (SMB), Microsoft Exchange servers will use direct-attached storage (DAS), which means storage access is limited to the Exchange server to which it is connected. SCSI disk arrays with a direct-attached tape backup device are typical for smaller Exchange configurations. Figure 1 describes a likely SMB environment for Exchange:
While this configuration works for a static environment, it presents expansion challenges. Storage growth will be limited to
Figure 1 - A Typical SMB Environment with Microsoft Exchange the number of SCSI devices that can be attached to the server. With higher capacity drives available today, administrators can postpone adding more servers and storage, but ultimately servers will reach bus capacity. Further, adding capacity to a direct-attached storage infrastructure can be disruptive to the applications in use, since the host will need to be shut down to incorporate the new storage devices. These disruptions can also extend into the traditional backup and restore window as restoring in a direct-attached environment will require the application to be restarted with a new data set which needs to be restored from tape. These processes are not only time consuming, but can be complex and error prone.
There is an additional problem associated with load balancing. Client systems, servers and storage all affect each other, and must be balanced so that users can access their E-mail and other data from the server in a reasonable time frame.
