Excluding files from a backup can take more time than actually save time if it is not done efficiently.
Internap Backup services rely on R1soft technology, a block-based backup system that can exclude files. This technology works well with a low number of exclusions but is inefficient when a large number of files/folders is excluded. If your backup takes longer than four hours to complete, Internap recommends you to review the backup policy settings as explained here:
If you have folders with several files that you wish to exclude from your backup policy, we suggest you contact Internap Customer Service Technical Support team to create a partition just for this folder. The partition table will be excluded entirely and will not take any time to be excluded.
Learn more about efficient file exclusion for backups in our blog post
Additional information can be found here http://wiki.r1soft.com/display/ServerBackup/Exclude+files+and+folders