Product Guide: Get a grip on Exchange server storage

It’s a Microsoft Corp. Exchange administrator’s job to make sure users don’t consume all of the disk space on Exchange servers. There are two main approaches: one is to use management tools to get e-mail use under control – to convince people they don’t need to save every e-mail they ever get; the other is to add disk space. To evaluate the options, we looked at a few of the top Exchange management tools, BindView Development Corp.’s bv-Control and bv-Admin combination, and NetIQ Corp.’s AppAnalyzer.

To evaluate storage options, we looked at several types of products to see what the trade-offs were between network-attached storage (NAS), storage-area networks (SAN), virtualization products and a storage product designed especially for Exchange servers. We selected Quantum Corp.’s Snap Server 4100 NAS server, XIOtech Corp.’s Magnitude SAN server and Dot Hill Systems Corp.’s SANnet Axis Server, with two of its storage modules, as being good representatives of the state of the art for their product types. Times N Systems Inc.’s TNS1600M storage system was intriguing because it was tailored as an Exchange-oriented storage product.

Whether you are trying to hold the line on your Exchange server’s store size or manage a large store, a management tool is the first step. While we liked AppAnalyzer, the ability of the bv-Admin/bv-Control combination to automate management tasks won us over. For smaller Exchange shops, a management tool might let you defer, or better yet avoid, the expense of adding storage.

Even with good management tools, most enterprise networks need to extend their storage beyond the Exchange server sooner or later. There are many good storage choices. For the budget impaired, Snap Server offers a good way to extend storage space and very attractive management tools. For a solution more integrated with Exchange, we were torn between the Magnitude SAN server and the SANnet Axis server with auxiliary storage modules. Both allowed for storage expansion without user downtime and let our servers boot off their disks.

Start with Management Tools

It’s easy to throw more disks at the problem, but letting your databases grow too large can lead to problems such as data corruption and performance degradation. This brings us to tools to manage your message stores.

AppAnalyzer helps you understand the state of your Exchange system and plan for growth. By default, AppAnalyzer imports data nightly from many data sources, such as the Exchange message tracking logs, mailbox and public folder records, and Internet domain databases. Limited-bandwidth networks may benefit from putting AppAnalyzer agents on remote servers to collect, compress and forward this data.

Using Internet Explorer we authenticated to the AppAnalyzer server and were presented with the AppAnalyzer Today page, which showed us the next data-collection tasks and reports to be run, as well as some recent results. We could add or modify data-collection tasks, see a more complete history or see currently running jobs.

AppAnalyzer’s power is in its reports. In addition to static reports, AppAnalyzer offers dynamic reports that let you change parameters. We generated a one-month mail-usage report and noticed one department sent a larger volume of mail than the rest. Within a few clicks, we found one user sent a lot of mail on one day, letting us start looking into what was sent and why.

You may create your own PivotTable reports, which can include charts and graphs, and can be scheduled to run automatically statically or dynamically. They can be saved to an FTP site or a shared network directory, or sent via e-mail, making it easy to distribute status reports. Because AppAnalyzer lets charges be assigned for Exchange services, such as sending an internal e-mail, receiving an external e-mail or amount of storage used, it is easy to automatically generate and deliver bill-back statements.

A One-two Punch

Bv-Control provides audit and reporting capabilities, while its companion product, bv-Admin, makes managing Exchange easier.

Bv-Control ties directly into Exchange data sources, letting you run reports on resources within your Exchange system. The results of queries can be saved as data sets, which can be used to track trends, such as changes in mail volumes and disk space used.

We captured two data sets to check the size of our public folder stores, then compared them to see how much they grew in a week. We not only saw our store had grown significantly, we saw whose collection of .PDF files caused the growth.

We especially liked the mailbox move feature, which let us move a user from one server to another with a simple drag and drop – even to different sites and from Exchange 5.5 to Exchange 2000. Additionally, we scheduled moves of users in batch mode to occur during off-hours without users – or administrators – present.

Featuring both a Microsoft Management Console snap-in and a Web-based interface, bv-Admin lets you manage objects in Exchange 5.5 and Windows NT domains, as well as Exchange 2000 and Active Directory, from either interface.

Further, roles can be created within bv-Admin to define who has rights to which parts of your Exchange and Windows system, letting you delegate responsibilities, and easily change the delegation when there are staff changes.

Bv-Control and bv-Admin work hand-in-hand to let you and delegated administrators keep your Exchange system under control. If an in-depth analysis tool is needed, AppAnalyzer’s great reporting flexibility, ease of use and ability to refine reports are attractive. On the other hand, if you need a good reporting tool that also can take action automatically, bv-Control and bv-Admin fit the bill.

Put Some Snap In It

In an Exchange server, there’s no substitute for adequate storage. Management tools can help make the most of your resources, but there is a good chance that even the most carefully managed resources won’t be enough. So, storage will need to be added.

The least expensive option is Snap Server. Each Quantum Snap Server 4100 NAS server can add 240GB or 400GB of storage in 1U rack space inexpensively. The bundled DiskXtender Appliance Edition software lets multiple Snap Servers look like a single storage pool.

Because Exchange stores must be on drives local to the Exchange server, we wondered how a NAS server could help an Exchange system.

Quantum’s EmailXtender Archive (EX/A) software can archive messages automatically out of the active message stores and onto Snap Server. The messages are replaced by links. As archived messages are read, they are retrieved from Snap Server, not the Exchange store, behind the scenes. We didn’t notice any difference in retrieval speed between messages still in the local store and those migrated onto Snap Servers.

Management of EX/A is quite simple but must be handled from the Exchange server. An Exchange distribution list defines whose mailboxes EX/A will maintain. We left the distribution list blank, so EX/A managed all the accounts. EX/A can delete messages from its own store based on aging criteria you select to reduce storage requirements. It’s also easy to restore archived messages back to the Exchange store.

The final touch was EX/A’s ability to restore messages that users have deleted. When a user deletes a message, the link to it is only deleted. The actual message remains on Snap Server for as long as your deletion policy allows. The messages can restored without using back-up tapes. Just don’t tell your users how easy it is, or you’ll be bailing them out all the time.

Get with the Times

The Times N storage system was designed to work with Exchange servers. Times N sent its TNS1600M storage virtualization product.

This preconfigured storage product for Exchange contained a shared memory unit (SMU) and three storage nodes. Each storage node was an Intel “white box” server, running Windows 2000 Server, containing 10 hot-swappable drives controlled by a RAID controller. Virtualization let us use the space on the storage nodes as if they were a single local drive.

A proprietary host bus adapter (HBA) is placed in each node that wants to use the Times N system. The HBAs have a fibre connection to the SMU. Times N uses a proprietary protocol but plans to move to industry-standard protocols.

How much space each storage node would share was determined during set-up. Then Times N’s Java-based utility, Team Builder, was used to create a virtual drive, taking logical disks from any number of storage nodes and assigning ownership to a single node in a few simple mouse clicks. Once that’s done, a new disk appears to the node that owns the new resource. At this point, the virtual drive is managed under Win 2000 like any local drive.

TNS1600M has some unique features. It lets you use your underutilized primary and back-up domain controllers as participating storage nodes. TNS1600M can automatically conduct mirroring from one virtual drive to another. The latest version of the software on the SMU is aware of Microsoft Windows Clusters and can provide automatic failover for these virtual drives. With our single-server configuration, we did not test this functionality.

Some caveats – changes such as adding physical disks or removing logical disks – may require rebooting the storage nodes and the servers attached to TNS1600M. Also, you cannot boot to a virtual disk using TNS1600M, as the Windows drivers aren’t available at boot time.

XIOtech Eelivers the Big Iron

XIOtech is a wholly owned subsidiary of Seagate, and it is making aggressive moves into the SAN market, setting new price/performance standards.

XIOtech sent its Magnitude SAN with 32 18GB drives. XIOtech includes on-site set-up of Magnitude, basic administration training and customized implementation guides. The customized guide for our installation was thorough, detailing needed floor space, electrical circuits and other environmental considerations, as well as providing a step-by-step guide.

Our server was connected to the SAN by an HBA using fibre-optic cables and Fibre Channel protocol, which is capable of transferring files at speeds up to 1Gbps. Each server on the SAN sees what it perceives as a physical disk of the size allocated by the system manager. While SANs are expensive, once the infrastructure is in place you can add disks, or even servers, for very little money.

Each Magnitude cabinet’s 32-disk capacity is divided into four drive shelves, each on its own SCSI channel.

An internal and dedicated PC, separate from the storage processor, acts as a management console, providing a simple interface to manage Magnitude. Each cabinet also can have up to eight independent Fibre Channel connections. An expansion cabinet doubles the drives and capacity to 11,520GB without requiring an additional controller.

We used Win 2000’s “dynamic” disk setting, which lets disks grow in size as needed. Adding disk space for our Exchange storage group is easy – add more hot-swappable disks to the Magnitude cabinet if needed.

Next, define a new logical disk and assign it to the Exchange server’s HBA. On the Exchange server, have the disk administrator rescan the disks to find the new space, extend the dynamic disk and make the added storage available for immediate use. All this happens with zero downtime.

Magnitude’s easy-to-use console graphically showed which virtual disks were connected to which HBA. A graph displayed throughput and operations on selected items. We kept tabs on how much our Exchange server was pushing Magnitude in relation to other boxes we had connected, all in real time.

With the graphic menus, it was easy to create a mirror of the disks we assigned to our Exchange server. Risking seven years of bad luck, we broke the mirror and reassigned the copy to another server. This makes recreating your environment for testing scenarios a breeze. Taking this one step further, we booted our server to disks on Magnitude.

Then, we brought the server down and assigned the disks to a different server with identical hardware. After the disks were assigned to the new server, we brought it up as if nothing had happened. This makes recovery times after a hardware failure almost instantaneous.

Head for the Hill

Dot Hill sent its Axis server storage manager. Axis performs storage virtualization of SAN devices on networks and any drives attached to Axis.

This lets each server connected to Axis see what it perceives as a physical disk of the size allocated by the system manager from the disks that Axis manages. Because Axis doesn’t include storage, we added a Dot Hill RAID Blade storage system to Axis’ very-high-density SCSI connector and a Dot Hill SANnet 7128 storage system to one of Axis’ two Fibre Channel connectors.

Axis offers a range of connectivity options. The Gigabit Ethernet and two 10/100Mbps Ethernet connections let Axis present storage as a NAS box to Windows/Server Message Block clients or Unix/Network File System clients. Client computers also can connect to Axis and the storage it manages either via Fibre Channel or SAN over IP. To boot the computers from disks that Axis manages, you need to use Fibre Channel, as the Windows SAN over IP client software is not available until after the client computer has finished booting.

For our Exchange system, we created a RAID 5 set on our RAID Blades and on our SANnet. We assigned both to our Exchange server via Fibre Channel.

A rescan of the available devices made them both available. We also used a 1000Base-FL adapter to connect to Axis using SAN over IP to achieve the same functionality.

After configuration of the client, the disks are presented to Windows in the same manner as the Fibre Channel disks. To get the most out of the connection, dedicate a fibre network interface card for the SAN-over-IP traffic.


All these products can help maximize storage space or provide additional storage space to your Exchange environment. Which is right for you depends on the size and growth potential of your environment.

The larger your Exchange system is, the more likely one of the software tools will be needed. They make it easy to control your Exchange environment. While AppAnalyzer’s reports were somewhat better than those from bv-Admin and bv-Control, we appreciated the ability to automate maintenance tasks with the BindView products.

Snap Server 4100 offers a lot of storage for the money, and a very reasonable way to expand storage. While Snap Server isn’t part of the Exchange server environment, the Quantum EX/A software made good use of the storage space.

If you have underutilized servers with extra drive bays on your network, Times N’s TNS1600M can get some use out of those systems, but overall, we’d rather look more seriously at an industry-standard SAN, at least until Times N uses industry-standard HBAs and protocols.

Dot Hill’s Axis combines different storage products you already own and manage up to 29TB of its own auxiliary storage modules. Better yet, it can make all the storage look like a single contiguous storage pool.

If you’re looking at making your first use of mass storage devices, you can’t go wrong with XIOtech’s Magnitude. It’s extremely easy to use, and XIOtech makes sure you’ll be up and running with your new storage in no time.

How We Did It

We installed Windows 2000 and Exchange 2000 onto a Compaq DL-380 server with twin Pentium III 1GHz processors, 512MB of RAM and an internal 18GB RAID 5 disk array. All management packages also were loaded on this machine.

The server was connected to a 100Base-T Ethernet, as were other hardware devices with Ethernet interfaces. When appropriate, other vendor-supplied cards, such as host bus adapters, were added to the Compaq server to facilitate communication with the other hardware devices.

The Exchange system was populated with user accounts, mail and public folder items so the software products would have something on which to report. The data stores were moved over to the storage provided by the hardware vendors where appropriate, but the Exchange install remained on the local Compaq RAID array.

It’s about Time

The TNS1600M is a preconfigured system designed for use in Exchange environments. It uses Windows 2000 on the three participating nodes, and the connecting system must also be Windows-based. However, this configuration also can support a Linux cluster.

Times N is about to release a product that will eliminate the need for its proprietary fibre connections and the shared memory unit. Instead, it will use high-speed industry-standard interconnects (such as Fibre Channel or Gigabit Ethernet) and local software drivers to achieve the same functionality.

Further design goals are to remove the restrictions on operating systems. Currently, and with the impending software-only solution, each participating and owning node must be running the same operating system. However, it is Times N’s goal to let any node, regardless of operating system, be a participating node. The only requirement would be a version of the software driver for that platform.

Berkley is supervisor of LAN Support Services at the University of Kansas. He can be reached