I have a question in regards to a statement on the following site: http://msexchangeteam.com/archive/2007/01/15/432199.aspx Maintenance Capacity A database that needs to be repaired or compacted offline will need capacity equal to the size of the target database plus 10%. Whether you allocate enough space for a single database, a storage group, or a backup set, this space needs to be available to perform these operations. This space can also be used when restoring a corrupted database. You can rename the corrupted database to prevent it from being overwritten during the restore in case your restore is bad and a repair is necessary. Question: If I have 5 databases spread across 5 different LUNs, do I need the 110% space extra for each LUN or across the entire Exchange server? Can I have a dedicated LUN with enough space so all Mainentance Capacity tasks can use this dedicated LUN instead of planning for an extra 110% space in addition to the 20% growth factor, whitespace factor, content indexing factor, etc..?

The extra space is just a working area. You can use "-t" in eseutil to specify to use another location's free space to work with. so while it would be nice, it isn't necessary to have 110% free on each volume.

Mike Crowley wrote: The extra space is just a working area. You can use "-t" in eseutil to specify to use another location's free space to work with. so while it would be nice, it isn't necessary to have 110% free on each volume. What about online maintenance? Online maintenance runs for every database. When the online maintenace runs for its respective database, won't it want the 110% space on that specific volume?

Found this piece of info from the technet library: Maintenance A database that needs to be repaired or compacted offline will need capacity equal to the size of the target database plus 10 percent. Whether you allocate enough space for a single database, a storage group, or a backup set, additional space will need to be available to perform these operations. So it seems that the 110% space is only for offline maintenance not for online maintenance tasks. So because of that, I think it'd be safe to assume that the 110% isn't mandatory for each volume that contains the database as you stated.

Yup. Leave free space, for wiggle room, but don't need 110% everywhere if you can't afford it.