cluster 1. (architecture) Multiple servers providing the same service. The term may imply resilience to failure and/or some kind of load balancing between the servers. Compare RAIS.
2. (file system) An elementary unit of allocation of a disk made up of one or more physical blocks. A file is made up of a whole number of possibly non-contiguous clusters. The cluster size is a tradeoff between space efficiency (the bigger is the cluster, the bigger is on the average the wasted space at the end of each file) and the length of the FAT. Last updated: 1996-11-04