Emc Corporation

Yeshayahu Hass

William Z Zahavi

Andrew M Shooman

Douglas Eric LeCrone

Natan Vishlitzky

Yoav Raz

Paul F Hale

Elcana Cohen

Kenneth R Coguen

A system provides mechanisms and techniques to retrieve trace data from a trace buffer residing in a data storage system. The software program operating on a processor within the data storage system operates in trace mode to produce trace data in the trace buffer upon occurrence of trace events. An event trace routine operates in response to a system call to access the trace buffer and return either a current value of a trace buffer pointer or the current trace buffer pointer as well as trace data read from the trace buffer beginning at a location and in an amount as specified in the system call to the event trace routine. The trace capture process can operate either within the data storage system or preferably on a remote host computer system to access trace data in the trace buffer in the data storage system by using the event trace routine. The trace capture process can periodically query the event trace routine with a frequency determined by an adaptive timing algorithm in order to detect the addition of trace data to the trace buffer. Upon detecting such a condition, the trace capture process can use the event trace routine to retrieve the trace data from the trace buffer. The trace capture process can also detect if trace data is written beyond the end of the trace buffer and can perform the proper sequence of trace data access operations using the event trace routine in order to provide continuous remote access to all trace data produced in the trace buffer.

Methods and apparatus for accessing trace data

This invention is a system and method for replaying workload data that may be accessed in a data storage environment and then replayed for testing or other reasons. The invention has the capability to extract a trace of all I/Os to a data storage system for an extended period of time and then replay these I/Os back to that or another system. Variables may also be manipulated though the play back system to increase testing flexibility at a lower cost than actually introducing new physical variables.

System and method for replaying workload data in a data storage environment

A method of communicating between first and second processes running on a plurality of host processors that are connected to a data storage system, the method including the steps of establishing a connection between the first and second processes through the data storage system; and by using the connection established through the data storage system, sending information between the first and second processes.

File transfer utility which employs an intermediate data storage system

A method and apparatus for emulating a magnetic tape storage device with a conventional, unmodified magnetic disk storage device. I/O output requests for the emulated magnetic tape storage device are intercepted to determine whether they involve a virtual tape resource that comprises a magnetic disk storage device. Tape requests to such a resource are converted into one or more conventional magnetic disk storage requests to effect an analogous operation. The size of the virtual tape resource can be reduced below the normal data capacity for the emulated tape storage device.

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Hod-Hasharon, Israel

Yeshayahu Hass