Backup up lots of small files from zfs unix client

i'm seeing if someone could help me on the below

i have a windows NBU 7.7 master server backuping up a solaris client using a zfs filesystem. Backups go to LTO 6 drives (VTL drive). One of the pools has got lots of small files. We can run a full backup with in a number of hours but i'm seeing if there are any other way to help speed up the backup?