Patent ID: 6088764
Filing Date: 2000-07-11
Classification: G06F

Abstract:
A method for reducing space allocation errors in a direct access storage device system comprising:in response to an indication that an initial space request for a first amount of space cannot be allocated, checking whether more than one volume of direct access storage can be used to satisfy the initial space request;if more than one volume can be used to satisfy the initial space request, allocating a first part of the initial space request on a first volume of direct access storage;if the initial space request has not been satisfied, allocating a second part of the initial space request on a second volume of direct access storage; andallocating additional parts of the initial space request on additional volumes of direct access storage, as necessary, until the initial space request has been satisfied;if the initial space request cannot be satisfied by using the second volume and the additional volumes, replacing a first extent limit on the number of extents that can be used to provide the initial space request with a second extent limit on the number of extents that can be used to provide a revised space request;reducing the initial space request by a preset amount to yield the revised space request;allocating a first part of the revised space request on the first volume of direct access storage using the second extent limit;if the revised space request has not been satisfied, allocating a second part of the revised space request on the second volume of direct access storage using the second extent limit; andcontinuing to allocate space on the additional volumes of direct access storage until the revised space request has been satisfied; or until a determination is made that the revised space request cannot be allocated on the additional volumes of direct access storage.