* Cemphore’s MailShadow is one DR option for SMBs using Exchange
If you work for a very large enterprise with a multi-million dollar annual budget for disaster recovery systems, you’ve probably already got your DR system in place for your Microsoft Exchange application. If, however, you work for a smaller organization and DR for Exchange is still on your “to-do” list, then I have a quick, easy and relatively cheap solution for you to look at.
Cemaphore Systems recently released a new version of MailShadow, its Exchange continuity and disaster recovery tool. MailShadow uses a transaction-based replication scheme to create select ghost mailboxes on an alternate live Exchange Server designated as the recovery server.
For every protected mailbox, all transactions on the primary server are transmitted to the recovery server so that the replicated mailboxes are always in sync. If a problem occurs with the primary Exchange Server, an administrator can switch all transactions over to the recovery server, which then takes over all processing without any loss of data. The failover can happen in minutes, often before users even notice a problem.
Unlike other enterprise disaster recovery tools, MailShadow has relatively low hardware and software requirements, making it easy and inexpensive to implement failover for your organization’s most important mail boxes. If you have multiple Exchange Servers, you already have much of what you need for disaster recovery. A MailShadow gateway synchronizes the primary and recovery sites. There’s no software to install on the Exchange server. Instead, MailShadow uses the MAPI protocol to extract and write transactions, creating a faithful replication of everything you do with a mailbox.
This is a pretty efficient solution in terms of bandwidth use. First of all, you don’t have to designate every mailbox for protection, only those that are most important to the organization. Then, only transactions for those specific mailboxes are transmitted over the WAN, rather than the data for the entire server. To increase efficiency, Cemaphore uses a proprietary transport protocol that uses buffering and compression to ensure high throughput.
MailShadow could be used as an Exchange migration tool, too. In the typical configuration, you have a primary site and a recovery site that are always in sync. Simply failover to the “recovery” site – which is actually your new upgraded Exchange Server – and make the failover permanent. The migration is instantaneous and there is no downtime at all, and you are assured that the migrated mailboxes are working fine before you remove the mailboxes from the original source mailbox. Compare this to the traditional process of moving mailboxes from one server to another. Moving even one large mailbox could take hours.
I talked to Alex Freund, president of the South Florida VAR 4IT. Freund implements MailShadow for many of his SMB customers who are on Microsoft Small Business Server. “It costs a lot of money to do a disaster recovery solution, especially for companies on SBS,” says Freund. “The Cemaphore design makes it easy to protect the most important mailboxes. This is really the only product we found that serves the small business market so well.”
Freund’s company acts as the outsourced IT department for most of its clients. “It was very important for us to find a product that is easy to manage. Our help desk staff can support MailShadow without a lot of expertise at the client site.”
Freund looked at traditional disaster recovery products like Double-Take. “Cemaphore doesn’t replicate the Exchange Store, so any corruptions aren’t replicated,” he says. “Also, when you dismount the Exchange Store, you aren’t certain if it will mount again. Since MailShadow runs on a second live Exchange Server, the Store is already mounted, so there’s no worry about it not coming back up.”
4IT has made it even easier for its clients to get the benefit of protected mailboxes. The VAR has set up MailShadow as a hosted solution and clients can replicate their selected mailboxes to an Exchange Server in the 4IT data center. “Living in South Florida, we have a lot of customers concerned about hurricanes and other disasters. Now we can offer them a hosted service for a small monthly fee that protects their critical e-mail assets without requiring an investment in additional hardware and software,” says Freund.
For technical details on how MailShadow works, read this October 2006 TechWorld review by Logan Harbaugh.
Other products that provide disaster recovery solutions for Microsoft Exchange include Microsoft’s own Windows Server 2003 Clustering Services; Availability Manager for Exchange from Quest Software; DigiVault from Lucid8; Neverfail for Microsoft Exchange from Neverfail Group; LifeKeeper from SteelEye Technology; Double-Take from Double-Take Software; and WANSyncHA Exchange from CA XOSoft;
