Patent ID: 7660832

Claim:
A computer system comprising: a server computer; a client computer; and a storage apparatus connected to the server computer, the storage apparatus having a database stored in a plurality of volumes, wherein the plurality of volumes respectively correspond to part or all of the physical storage regions of the database; wherein the server computer is configured to execute the processes of table conversion stored in the database, wherein each time the table conversion is finished, the tables are given fresh numbers in the order of being completed; wherein the sewer computer is farther configured to produce a snapshot of the plurality of volumes included in the plurality of tables each time any one of the plurality of tables is finished in conversion of the any one of the plurality of tables, wherein the storage apparatus includes a copy volume to store copy data, at a first time point, of the volume in which the database is stored; and wherein the server computer orders the storage apparatus to produce a backup, after the first time point, of the volume including the plurality of tables when any one of the conversion table ends normally; and when any one of the conversion tables stops abnormally: the server computer orders the storage apparatus (i) to overwrite a volume of the storage apparatus, in which the database at a time of the abnormal end of conversion is stored, with a snapshot selected from among the plurality of snapshots which corresponds to a latest snapshot obtained at the time of the abnormal end of conversion, (ii) to specify data corresponding to the abnormally stopped table from the selected snapshot and overwrite the volume, in which the overwritten volume is stored in (i), with the specified data corresponding to the abnormally stopped table to recover contents of the abnormally stopped table, wherein the specified data corresponding to the abnormally stopped table is determined based on states of execution associated with the conversion process performed on the abnormally stopped table.