Methods of processing files in a multiple quality of service file system

Abstract

The invention relates to a multiple QoS file system and methods of processing files at different QoS according to rules. The invention allocates multiple VLUNs at different qualities of service to the multiQoS file system. Using the rules, the file system chooses an initial QoS for a file when created. Thereafter, the file system moves files to different QoS using rules. Users of the file system see a single unified space of files, while administration place files on storage with the new cost and performance according to attributes of the files. A multiQoS file system enhances the descriptive information for each file to contain the chosen QoS for the file.

1 . A method of processing files in a multiQoS file system, comprising:
 (a) reading a migration rule;   (b) reading a file having an attribute, a current QoS, and blocks;   (c) testing if the file is identified for migration and if not:   (d) computing a new QoS by comparing the migration rule to the attribute; and   (e) testing if the current QoS equals the new QoS and if not, indicating that migration is in progress.   
     
     
         2 . The method of  claim 1 , wherein the migration rule includes a value of file activity. 
     
     
         3 . The method of  claim 1 , wherein the migration rule includes a value of capacity threshold. 
     
     
         4 . The method of  claim 1 , wherein the migration rule includes a value of file size. 
     
     
         5 . The method of  claim 1 , wherein the extension of the file name defines the current QoS. 
     
     
         6 . The method of  claim 1 , wherein the file attribute includes a migration flag and step (e) includes setting the migration flag. 
     
     
         7 . The method of  claim 1 , wherein the file attributes and the addresses of the blocks are held in an i-node of the multiQoS file system. 
     
     
         8 . The method of  claim 1 , further comprising a step of (f) migrating the file to a VLUN having an identifier corresponding to the new QoS. 
     
     
         9 . The method of  claim 8 , wherein the method repeats steps (a)-(f) for another file. 
     
     
         10 . The method of  claim 8 , wherein the blocks have addresses, further comprising a step (g) allocating blocks in the new QoS VLUN; (h) copying the blocks from the old QoS VLUN to the blocks allocated in the new QoS VLUN; and (i) releasing the blocks in the old QoS VLUN. 
     
     
         11 . The method of  claim 1 , wherein step (b) uses a preallocation size from the CIFS protocol as the file size. 
     
     
         12 . A method of migration of a file between QoS in a multiQoS file system when a file offset is less than the total number of blocks of the file, comprising
 (a) placing a read lock on the file;   (b) finding the block addresses for a chunk of the file starting with the file offset;   (c) unlocking the read lock and reading the blocks found in step (b);   (d) allocating new blocks for the chunk of the file in a new QoS VLUN;   (e) placing a write lock on the file;   (f) copying the old blocks to the new blocks;   (g) updating the file attributes to the new QoS;   (h) putting the old blocks on the free list;   (i) committing the transaction and unlocking writes; and   (j) adding the file offset to the chunk size to get the value of file offset.   
     
     
         13 . The method of  claim 12 , wherein the step (g) includes updating the file attributes to point to the new blocks. 
     
     
         14 . A method of migration of a file between QoS in a multiQoS file system, comprising:
 iterating through the blocks of a file;   allocating new blocks in a new QoS, wherein the blocks in each QoS contain an index in certain bits of their block address indicating the QoS;   copying the data from the old blocks to the new blocks for each block of the file;   adjusting the attributes of the file to point to the new blocks; and   freeing the old blocks.   
     
     
         15 . The method of  claim 14 , wherein the step of allocating new blocks includes allocating copying and freeing small chunks at a time. 
     
     
         16 . A method of migration of a large file including extents, between different QoS VLUNs in a multiQoS file system, comprising
 (a) placing a read lock on each extent;   (b) finding the block addresses for each extent;   (c) unlocking the read lock and reading the blocks found in step (b);   (d) allocating new blocks for each extent in a new QoS VLUN;   (e) placing a write lock on each extent;   (f) copying the old blocks to the new blocks;   (g) updating each extent's attributes to the new QoS;   (h) putting the old blocks on the free list;   (i) committing the transaction and unlocking writes; and   (j) resetting the migration flag.   
     
     
         17 . The method of  claim 16 , wherein the step (h) includes resetting the rule attribute and updating the extent attributes to point to the new blocks.