One of the major benefits that the SRM v2.2 specification brought was the introduction of the concept of spaces. A space is a reserved portion of dCache's total capacity. It allows file upload operation to be conducted with some certainly that sufficient space is available.

dCache's implementation of SRM spaces is an example of late pool binding. This is an advanced feature that means that, although dCache will (under normal operating conditions) always honour space reservations, dCache does not choose on which pool a file will be stored until a user uploads the file.

One of the benefits of late pool binding is that dCache doesn't waste storage capacity. When a space reservation isn't being completely used, some of the capacity can be used for other activity. One possible use of this capacity is providing temporary cached copies of data. This allows dCache to spread read requests for “hot” files over multiple pools, so increasing the throughput.

In dCache, space management operations (reserving space or using space) operate on LinkGroups. A LinkGroup contains one or more Links and include SRM specific concepts and settings. Broadly speaking, this section is about LinkGroups.