| US 7,549,032 B1 | ||
| Using data copies for redundancy | ||
| Anand A. Kekre, Pune (India); and Ankur P. Panchbudhe, Nagpur (India) | ||
| Assigned to Symantec Operating Corporation, Cupertino, Calif. (US) | ||
| Filed on Sep. 28, 2007, as Appl. No. 11/864,029. | ||
| Application 11/864029 is a continuation of application No. 10/741858, filed on Dec. 19, 2003, granted, now 7,290,101. | ||
| Int. Cl. G06F 12/00 (2006.01); G06F 13/00 (2006.01); G06F 15/80 (2006.01) | ||
| U.S. Cl. 711—162 [711/114; 711/154; 709/216] | 16 Claims |
| 1. A method comprising:
generating an I/O transaction to read data from or write data to memory that is allocated to store data of a first data block
of a data volume, wherein the data volume comprises a plurality of data blocks including the first data block;
in response to generating the I/O transaction, reading an entry of a map in memory, wherein the map comprises a plurality
of entries, wherein each entry of the map indicates whether memories allocated to store data of respective data blocks of
the data volume and a point-in-time (PIT) copy thereof, contain identical data;
if the entry in the map indicates that identical data is stored in memories allocated to the first data block of the data
volume and a first block of the PIT copy, respectively:
reading data from memory allocated to store data of the first block of the PIT copy; and
allowing the I/O transaction to complete using the data read from memory allocated to store data of the first block of the
PIT copy, without first accessing a transaction log associated with the data volume.
|