Virtual Disk Storage Techniques
First Claim
1. A computer-readable storage medium including instructions that upon execution by a processor cause the processor to:
- instantiate a log for a virtual disk file in random access memory, the log including ordered log entries;
identify a log entry in the log, the log entry being the oldest log entry in the log that was generated after a request to commit cached input/output jobs to a storage device was issued;
add an identifier for the identified log entry to a newly generated log entry; and
write the newly generated log entry to the log.
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Accused Products
Abstract
This document describes techniques for effecting a virtual disk. In an exemplary configuration, a virtual disk file can be associated with a log that acts as both a log and a check point record. When a log entry is generated, information that identifies the tail can be stored therein. This information can be used in the event that virtual disk file is improperly closed, i.e., a crash or power failure occurs, to discover a sequence of log entries to replay. In addition to the foregoing, other techniques are described in the claims, detailed description, and figures.
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Citations
20 Claims
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1. A computer-readable storage medium including instructions that upon execution by a processor cause the processor to:
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instantiate a log for a virtual disk file in random access memory, the log including ordered log entries; identify a log entry in the log, the log entry being the oldest log entry in the log that was generated after a request to commit cached input/output jobs to a storage device was issued; add an identifier for the identified log entry to a newly generated log entry; and write the newly generated log entry to the log. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A computer system, comprising:
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a processor; a memory in communication with the processor when the processor is supplied with power, the memory comprising instructions that upon execution cause the processor to; access a log for a virtual disk file, the log including log entries written in a sequential order; select a sequence of log entries in response to a determination that each log entry in the sequence is valid, the sequence includes a newest valid log entry, and that each log entry was written to the log after a discontinuity in the log file; and apply changes to sectors of the virtual disk file identified by the sequence of log entries. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A computer implemented method, comprising:
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instantiating a virtual disk for a virtual machine, the virtual disk backed by a virtual disk file; determining a bit pattern to write to the virtual disk file; generating a log entry including the bit pattern to write to a log, the log including ordered log entries, the log stored in random access memory; adding an identifier for an oldest unflushed log entry to the log; and writing the log entry to the log. - View Dependent Claims (19, 20)
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Specification