The present invention provides a storage system for storing variable sized objects. The storage system is preferably a transaction-based system that uses variable sized objects to store data. The storage system is preferably implemented using arrays disks that are arranged in ranks. Each rank includes multiple stripes. Each stripe may be read and written as a convenient unit for maximum performance. A rank manager is able to dynamically configure the ranks to adjust for failed and added disks by selectively shortening and lengthening the stripes. The storage system may include a stripe space table that contains entries describing the amount of space used in each stripe. An object map provides entries for each object in the storage system describing the location (e.g., rank, stripe and offset values), the length and version of the object. A volume index translates regions of logical storage into object identifiers. The storage system may implement various types of formats such as I-node, binary tree and extendible hashing formats.