Browse Prior Art Database

Data Migration and Staging Facility

IP.com Disclosure Number: IPCOM000079333D
Original Publication Date: 1973-Jun-01
Included in the Prior Art Database: 2005-Feb-26
Document File: 3 page(s) / 92K

Publishing Venue

IBM

Related People

Brawn, B: AUTHOR [+2]

Abstract

A supervisorial controller is illustrated for automatic administration and control of a computer system's secondary storage resources, during the normal operation of the computer system. The Migration/Staging Monitor (MSM) 10 responds to events from many interfaces, to control the occurrence of general migration, immediate migration, and staging.

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Data Migration and Staging Facility

A supervisorial controller is illustrated for automatic administration and control of a computer system's secondary storage resources, during the normal operation of the computer system. The Migration/Staging Monitor (MSM) 10 responds to events from many interfaces, to control the occurrence of general migration, immediate migration, and staging.

The Migration/Staging Monitor 10 is a centralized controller for all Data Migration/Staging (DMS) run-time activities. It is event driven and acts as a first level event processor. The three parts of the MSM are Initialization, Event Processing and Termination/Recovery. The MSM is instrumented to record events and summarize DMS activity. Summary data is periodically written out, so that an abbreviated log of all DMS activity is available as a permanent record. When requested by the operator or a privileged user, the Migration/Staging Trace Writer (MSWTR) 11 is activated to write out event trace data. These measurements thus are available for analysis and subsequent refining and tuning to improve performance.

The General Migration Task (GMT) 12 is initiated by the MSM when a request is received either from:
(a) The Device Allocation Interface (DAI) 13 when a

nonspecific volume allocation request cannot be satisfied.
(b) The Space Assessment Task (SAT) 14 (a subtask of the MSM)

when a given threshold of overall space available across

the resident volumes is violated. (The SAT periodically

makes a check of available space on resident volumes.)
(c) The operator 15 as part of a regular operations procedure.

The GMT 12 scans through an inventory of all authorized data on the system and invokes a given algorithm to make the decision as to what data to migrate. The program design permits simple redefinition of the decision algorithm, so that with experimentation the appropriate algorithms can be chosen to optimize the selection procedure.

An Immediate Migration Task (IMT) 16 is initiated by the MSM whenever it receives a request from:
(a) The Space Allocation Interface (SAI) 17, 18 when there is

not enough space on a volume to satisfy a specific volume

allocation request.
(b) The SAT 14 determines that the space available on a

particular volume falls below a given threshold.
(c) The Space Allocation Interface 17, 18 when a given user

request for space exceeds the amount permitted to him on

the on-line data base.
(d) The MIGRATE command 19, 20, or batch equivalent, when a

user requests that some of his data be moved off-line

"immediately."

The IMT 16 performs by-user or by-volume migration. Again, on the by-volume migration, the decision algorithm is modifiable.

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By-volume migration is only performed if not enough space can be recovered, by first scratching all unneeded temporary data from the volume and any data which is not in the inventory of authorized data. More than one IMT can coexist in the system simultaneously.

Archiving of data is actuall...