Path maintenance mechanism

Abstract

In the computer system including a host computer and a storage system, the storage system includes a physical disk and a disk controller, and provides a storage area of the physical disk as at least one logical unit. The processor obtains, at a first time point and a second time point different from the first time point, a relation between a logical path and a component through which the logical path passes, stores, as logical path connection information, the relations obtained at the first time point and the second time point, refers to the logical path connection information to compare the logical paths existing at the first time point and the logical paths existing at the second time point with each other, and specifies the logical path which does not exist at the second time point among the logical paths existing at the first time point.

1 . A path management method for a storage system providing a plurality of logical units and a host computer accessing the logical units using a path, wherein the path logically includes a Host Bus Adapter (HBA) in the host computer, a storage port in the storage system, and one of the plural logical unit as components, the path management method comprising the steps of:
 storing first path information indicating components logically included in each of a first plurality of paths existing in a first time; and   storing second path information indicating components logically included in each of a second plurality of paths existing in a second time;   wherein for a certain component said path management method further comprising the steps of:   calculating a first number of a path logically including the certain component in the first time, based on the first path information,   calculating a second number of a path logically including the certain component in the second time, based on the second path information, and   with emphasis, displaying an ID of the certain component, the first number, and the second number, if the first number and the second number are different.   
     
     
         2 . A path management method according to  claim 1 , the method further comprising the steps of:
 specifying a certain path included in the first plurality of paths and not included in the second plurality of paths; and   displaying an ID of the certain path and IDs of components logically included in the certain path.   
     
     
         3 . A path management method according to  claim 1 , the method comprising the steps of:
 receiving inputs for designating the first time and the second time.   
     
     
         4 . A path management method according to  claim 1 , the method comprising the steps of:
 executing a multi-path program by the host computer to manage a path status of the path and to use a path status having an online status;   displaying path statuses of the second plurality of paths;   receiving input designating a path among the second plurality of paths; and   changing a path status of the designated path to a different status.   
     
     
         5 . A computer to be configured to manage a storage system providing a plurality of logical units and a host computer accessing the plurality of logical units using a path, wherein the path logically includes a Host Bus Adapter (HBA) in the host computer, a storage port in the storage system, and one of the plurality of logical units as components, the computer comprising:
 a memory which stores first path information indicating components logically included in each of a first plurality of paths existing in a first time, and second path information indicating components logically included in each of a second plurality of paths existing in a second time; and   a processor to be configured, for a certain component, to calculate a first number of path logically including the certain component in the first time, based on the first path information, calculate a second number of path logically including the certain component in the second time, based on the second path information, and with emphasis, display an ID of the certain component, the first number and the second number, if the first number and the second number are different.   
     
     
         6 . A computer according to  claim 5 , wherein the processor is further configured to specify a certain path included in the first plurality of paths and not included in the second plurality of paths, and display an ID of the certain path and IDs of components logically included in the certain path. 
     
     
         7 . A computer according to  claim 5 , wherein the processor is further configured to receive inputs for designating the first time and the second time. 
     
     
         8 . A computer according to  claim 5 , wherein the processor is further configured to execute a multipath program by the host computer to manage a path status of the path and to use a path status having an online status, display path statuses of the second plural path, receive input designating a path among the second plurality of paths, and change a path status of the designated path to different status. 
     
     
         9 . A computer according to  claim 5 , wherein the computer is a management server which is different than the host computer. 
     
     
         10 . A computer according to  claim 5 , wherein the computer is the host computer. 
     
     
         11 . A computer system comprising:
 a storage system providing a plurality of logical units;   a host computer accessing the plurality of logical units using a path; and   a management server,   wherein the path logically includes a Host Bus Adapter (HBA) in the host computer, a storage port in the storage system, and one of the plurality of logical units as components,   wherein the management server is configured to store first path information indicating components logically included in each of a first plurality of paths existing in a first time, and store second path information indicating components logically included in each of a second plurality of paths existing in a second time, and   wherein the management server includes a processor to be configured, for a certain component, to calculate a first number of path logically including the certain component in the first time, based on the first path information, calculate a second number of path logically including the certain component in the second time, based on the second path information, and with emphasis, display an ID of the certain component, the first number and the second number, if the first number and the second number are different.   
     
     
         12 . A computer system according to  claim 11 , wherein the management server is further configured to specify a certain path included in the first plurality of paths and not included in the second plurality of paths, and display an ID of the certain path and IDs of components logically included in the certain path. 
     
     
         13 . A computer according to  claim 11 , wherein the management server is further configured to receive inputs for designating the first time and the second time. 
     
     
         14 . A computer according to  claim 11 , wherein the management server is further configured to execute a multipath program by the host computer to manage a path status of the path and to use a path status having an online status, display path statuses of the second plurality of paths, receive input designating a path among the second plurality of paths, and change a path status of the designated path to a different status. 
     
     
         15 . A computer system according to  claim 5 , wherein the management server is another host computer.