Exchange Backup -- Simplified
June 28, 2006
Microsoft Exchange Server 2003 was first touted for its capability to resolve most of the problems of backup and restore within an Exchange environment. Yet it appears that the hassle is far from over. Even the widely hyped concept of Exchange Storage Groups, which allows backup and recovery and migration of a single storage group, is not without issues.
"Exchange can only do single-instance store within a storage group, so attachments that go to five users in my five different Storage Groups now get backed up five times," says W. Curtis Preston, vice president of data protection at storage consultancy GlassHouse Technologies. "In addition, I must back up the Information Store (or the Storage Group) and the mailboxes if I wish to recover both easily."
That means a lot of extra work for the storage administrator. If the storage admin wants to be able to do a full restore of Exchange, the entire Information Store must be backed up. If she wants to be able to recover individual mailboxes without jumping through hoops, all the mailboxes have to be backed up a slow, painful process.
Then why are there so many vendors in this space? The answer appears to be that the Microsoft backup arena represents a goldmine for potential income. As Microsoft continues its relentless push into the enterprise, the Windows backup pie just keeps growing and growing.
"The Exchange backup market is huge and consists of dozens of competing vendors," says Preston. "They differentiate themselves via really nice interfaces that make backup and recovery easier, or they fix it altogether by working around Exchange."
The latter group, he says, use continuous data protection (CDP) technology to solve the Exchange backup blues. They achieve this by providing both Information Store and mailbox recovery without backing up either in the traditional way.
No Second Server
Enterprises that use Exchange Server 2003 will tell you it is much better than its predecessor. It adds the flexibility of recovering a Mailbox Information Store without requiring a physical secondary recovery server located in a different Active Directory Forest, an unfortunate fact of life in previous versions. Now the Mailbox Store can be restored to the same system as the production server.
"Recovery Storage Groups simplify the recovery of individual mailboxes and mailbox items, which allow administrators to restore items at a granular level without having to perform bricks-level backups and without affecting the production Exchange database," says Peter McLaughlin, a GlassHouse consultant.
In addition to Recovery Storage Groups, Windows 2003 Server incorporates a feature called Volume Shadow Copy Service (VSS). This built-in feature enables third-party backup products to backup a snapshot of the Exchange Storage Groups. The snapshot happens in seconds and goes unnoticed by the end user. By backing up a snapshot copy of the Storage Group, the production Storage Groups avoid impact and hindered performance. This method lends flexibility by opening backup Windows to times during peak and non-peak hours.
That said, the No. one complaint, according to GlassHouse, remains granularity. Case in point: There is no proven method for performing bricks-level backups.
"The problem with bricks-level backups is that they simply take way too long and offer too much of a performance hit on the Exchanger Server system," says McLaughlin. "The ability to back up Exchange at an item level would ease the ability to recover Exchange items such as a calendar appointment, individual e-mails or contacts without having to restore an entire Exchange database."
Such limitations, however, haven't inhibited anyone from Fortune 500 giants to "mom and pop" shops from running their own Exchange Server environment. According to a Radcati Group study, the small business market (defined as businesses with fewer than 100 employees) holds 35 percent of the Exchange market share, making it the largest installed base. Radcati estimates there will be 140 million active mailboxes on Exchange Server systems in 2006, and that number will rise to 200 million by 2009.
What's Out There
It's no surprise, then, to find at least 40 vendors in the Exchange space. Let's focus on two of them one is a recognized name in storage, and the other is in the startup category.
CA offers ARCserve as an answer to skyrocketing e-mail volume. The enhanced cluster support in Exchange 2003 allows customers to keep their e-mail system running if the primary server or location has a hardware or software failure. However, the Exchange Admin has to check that the backup application fully supports a clustered environment like ARCserve backup.
"One of the problems still present for customers is the ability to restore individual mailboxes in case of a failure," says Frank Jablonski, director of BrightStor product marketing at CA. "Administrators can restore the last snapshot, but they can't retrieve individual mailboxes without the use of a solution like CA's ARCserve backup."
Another problem this third-party tool solves is disaster recovery. In the event of a disaster, the user must reinstall the application before recovering the databases, and this can take a long time unless a bare-metal recovery option is available, as found in ARCserve.
Jablonski suggests organizations look for a Microsoft-certified solution that provides flexibility and performance for backup and recovery. It should be able to make use of the latest backup methodologies, such as VSS and disk-based backup, to minimize the backup time and provide the fastest recovery time. It must be able to take a backup in a consistent state, since this keeps Exchange from performing a long process to restore consistency and dramatically improves recovery time. It should be able to back up granular document-level data and restore individual mailboxes, notes, calendars, and contacts easily and quickly. And it should also be able to report status and send alerts if any problems are incurred.
"With the introduction of the VSS backup technology, Exchange 2003 can now be easily backed up using software- or hardware-based snapshot technology," says Jablonski. "This drastically reduces the backup time as well as the impact on the Exchange server and the users."
There is still room, he believes, for Microsoft to improve the backup and recovery of Exchange by adding features, such as public folder support, more granular recovery, and scriptable interfaces to help with administrative tasks.
Storage startup Teneros takes a different approach. Instead of backup software, it offers an appliance that IT guys don't have to touch. This is touted as a 15-minute installation, no intrusive agents added to Exchange server, and maintenance is done at Teneros' Network Operations Center. Prices are in the $15,000 to $30,000 range. Rather than being a backup/restore appliance, Teneros characterizes its box as a failover appliance.
"We hear continuing complaints from our customers that backups are often corrupted," says Andrea Skov, vice president of marketing and business development at Teneros. "What Teneros provides is end user Exchange continuity and fully functioning e-mail when the Exchange server is down for regular maintenance, restoration of a corrupt mail store, or some other unplanned outage."
A full copy of the message store is maintained in the appliance, which can, in the event of a total loss of the mail store on the Exchange server, replicate the full mail store back to the Exchange server while continuing to provide full e-mail capability to end users.
For all the criticisms of Exchange, one thing is clear. Backing up and restoring is a far easier than it was before. And that trend of improvement can be expected to continue. That doesn't mean, however, that we will eventually arrive at a point where it is all plug and play.
"No backup solution can work magic," says McLaughlin. "End users should expect to invest time, effort, and money into their Exchange backup solution. This should include extensive planning, testing, and monitoring."
This article was originally published on Enterprise Storage Forum.