The Argument for Smaller Email Inboxes
Written by Paul Mah on February 3, 2011
The release of Microsoft Exchange 2010 substantially increased the maximum database size that can be handled by its core messaging engine to 16TB (Terabyte). This is 10 times more than the 200GB (Gigabyte) supported in Exchange 2007, and must appeal to companies looking to support more users or larger mailbox quotas. Of course, the maximum supported size does not necessarily conform to best practice sizes recommended by Microsoft, for which the Microsoft Exchange team has released a detailed spreadsheet documenting the various scalability limits here. (You will need Excel 2007 and later to open it)
Regardless of the Exchange Server version in use, enterprises have a number of techniques to support the needs of their organization. What I want to talk about today however, are some considerations that email administrators and IT managers should evaluate prior to upping the limits on their corporate inbox.
Computing the storage cost
The most obvious argument against large mailboxes would of course be the dollar cost that acquiring additional storage space will incur. While hard disk storage has plunged in recent years, assigning 10GB inboxes instead of 2GB or even 5GB ones does add up to a hefty amount. In addition, there is also a need to factor in the cost of data mirroring technologies too, which can result in a doubling of storage space if RAID1 is used, for example. Factor in the corresponding increase necessary for offline or archival storage, and the storage requirements goes up higher still. Clearly, performing a linear computation multiplying users with their mail quota is not an accurate way to determine the true cost of any increase in quota.
The Microsoft Outlook equation
Email administrators must also remember to consider the Microsoft Outlook clients deployed in their organization before committing to a large mailbox quota. The reason is simple; old versions of Outlook have much lower limits than those found in recent versions of Exchange Server. Outlook 2002 and earlier for example, have an overall size limit for personal folders (.pst) file of just 2 Gigabytes, though the default configuration for Outlook 2003 and Outlook 2007 allows for up to 20GB when configured in non-IMAP and HTTP configurations. Actual limitations aside, anecdotes and my personal experience do indicate a certain amount of performance deterioration in Outlook when working with excessively sized mailboxes.
Of course, the limiting factors highlighted above are not found in Outlook Web App (OWA), which has been steadily growing in functionality and usability. Using OWA exclusively though, would mean that some of the capabilities I’ve highlighted in Useful Features in Outlook and Exchange that you may have Missed will not be available.
Potential challenges to backup and disaster recovery
One factor that is not immediately obvious when making a decision to loosen email quotas is the additional burden forced upon existing disaster recovery processes. Doubling mail storage space could conceivably double the amount of time required when performing nightly data backup, for example. In addition, the purchase of faster network equipment or backup appliances might even be required should the backup window be exceeded due to the additional time incurred. The same set of challenges applies to disaster recovery, and in the worst case scenario might require the reworking of existing business continuity strategies to meet your company’s recovery time objective.
The actual needs of users
Compliance requirement aside, administrators need to evaluate if users will truly benefit from an increased mail quota. Does doubling storage quota bring about genuine productivity gains, or does it simply represent capacity that will be squandered away in a couple of months? Hence administrators should not be fixated about computing storage costs and solving technical constraints, but should instead focus on determining the derived value of a larger inbox. And yes, five-years-old emails might be better off archived in an off-line system.
Another consideration is how the amount of large multimedia files that users are transferring has grown over the years. As such, a pertinent question would be whether precious storage space is being wasted by large, unwanted attachments. Microsoft added Search Folders into Outlook 2007 onwards, and you might want to use this tool to check whether users in your organization are guilty of sending large attachments. I did a quick check and despite my aggressive elimination of large attachments, found that 15% of my mailbox space was taken up by attachments of 1MB and more.
Posted in email management, Exchange server | 2 Comments »
February 17th, 2011 at 12:43 am
I’m all for a larger mailbox quota where offline archiving is not available, simply because if a lower quota is allocated, users will tend to use a PST file for storage on a local disk (networked PSTs are not supported or recommended) which of course is never backed up. Users always shout loudly when they lose “archived” emails due to a workstation’s disk crash. Outlook’s autoarchiving needs to be disabled too for the same reason.
Outlook 2003/2007′s default unicode PST limit is 20GB (2010′s is 50GB), which is a soft limit configured in the registry up to a hard limit of 32TB. This also applies to OST files. Performance does deteriorate over 20GB, but not massively so from my limited testing. A 20GB+ OST can also easily be achieved when opening multiple smaller mailboxes under the same profile.
The storage requirements and backup window only really start to become factors in medium to large businesses where the sheer number of users can cause both elements to rocket. For the small business (<30 users), certainly for the last few years, adequate storage for large mailboxes is often available, and the overall size usually fits comfortably in the available backup window.
February 25th, 2011 at 3:14 pm
I am all for big inboxes too. Sometimes I don’t want to make the decision of which e-mail to delete simply because I have no more space. These e-mails are all important to me.