Will I be able to use the OCS/Lync Server report pack if I don't have an archive database?
Yes you will still be able to use the OCS/Lync Server Report pack. However some data will not be available in the 6 reports under the Instant Messages node, and the 5 reports under File Transfers node. These reports have insertable columns for showing IM Volume in KB and File transfer Volume in MB. These columns will show up as blank as an archive database is required in order to gather this information from the OCS/Lync environment.