Appeal 2007-1352
Application 10/406,127
3. Duprey teaches that the master storage unit 130 stores a write entry in
the write intent log when it receives a write request from the host 110.
(Col. 4, ll. 27-29; col. 5, ll. 61-62; Fig. 1.) The write entry includes
information identifying an affected portion of the mirror image and
also may include the actual data to be written to the mirror image.
(Col. 4, ll. 29-33.) During normal operation, the master storage unit
130 maintains the write intent log in the write cache of a storage
processor 204. (Col. 4, ll. 37-40; col. 6, ll. 62-67; col. 7, ll. 12-17;
Figs. 2-3.) The master storage unit 130 may have redundant storage
processors 204, 208 that maintains a write intent log that also is
replicated on the peer storage processor so that one storage processor
may take over if the other storage processor fails. (Col. 4, ll. 42-48.)
After the master storage unit 130 stores a write entry in the write
intent log, it then updates the master image and the slave images
based upon the write request received from the host 110. (Col. 4, ll.
58-61; col. 16, ll. 3-18; Fig. 6.) The master storage unit 130 deletes
the write entry from the write intent log once it is no longer needed.
(Col. 4, ll. 61-65.)
4. Duprey teaches that the write intent log is stored in non-volatile
storage if the master storage unit 130 fails. (Col. 5, ll. 31-33.)
Following a failure, the master storage unit 130 resynchronizes the
slave images to the master image by updating only the portions of the
slave images identified in the write intent log. (Col. 5, ll. 42-49;
Fig. 9.) Duprey also teaches that the write intent log may be restored
7
Page: Previous 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Next
Last modified: September 9, 2013