Abstract: Techniques for synchronization for cross-context digital item containers and collaboration are provided, receiving a user command to share a particular digital item from a first portfolio of digital items with a second portfolio of digital items. In response receiving the command to share the digital item, making a digital copy of it and placing it in the second portfolio of digital items. Subsequently, an alteration is made to the digital item and a determination is made with whom to share the alteration among those with whom the digital item had been previously shared. Those alterations can be accepted (or rejected) by the other portfolios. When they are accepted, they are applied to the digital copy.

Abstract: A technique quantifies logical storage space trapped in an extent store due to overlapping write requests associated with volume metadata managed by the volume layer. The volume metadata is illustratively organized as a multi-level dense tree metadata structure, wherein each level of the dense tree metadata structure (dense tree) includes volume metadata entries for storing the volume metadata. When a level of the dense tree is full, the volume metadata entries of the level are merged with a next lower level of the dense tree in accordance with a merge operation. Illustratively, the technique may be invoked during the merge operation to examine the volume metadata entries at each level of the dense tree involved in the merge and determine the LBA range overlap of the entries.