Browse Prior Art Database

Method for Dynamically Managing Virtual Storage Pools

IP.com Disclosure Number: IPCOM000104089D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 79K

Publishing Venue

IBM

Related People

Manners, DC: AUTHOR

Abstract

Disclosed is a method for optimal management of a virtual storage pool on a virtual storage operating system such as MVS/ESA*. The essence of this method is to determine whether unused allocated virtual storage should be returned to a pool of unused virtual storage elements for rapid retrieval later, or deallocated to the operating system to permit system resources associated with the storage to be redistributed across other executing programs.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 53% of the total text.

Method for Dynamically Managing Virtual Storage Pools

      Disclosed is a method for optimal management of a virtual
storage pool on a virtual storage operating system such as MVS/ESA*.
The essence of this method is to determine whether unused allocated
virtual storage should be returned to a pool of unused virtual
storage elements for rapid retrieval later, or deallocated to the
operating system to permit system resources associated with the
storage to be redistributed across other executing programs.

The following definitions are pertinent to the description of this
method:

1.  Storage element:  a contiguous area or block of virtual storage
    allocated from the operating system.

2.  Idle storage element:  a storage element not currently being
    used.

3.  Storage pool:  a collection of idle storage elements.

4.  Storage pool size:  the current count of idle storage elements
    residing in a storage pool.

5.  Storage pool threshold:  the maximum number of idle storage
    elements permitted to reside in a storage pool.

6.  Idle instance count:  the count of instances of obtaining a
    storage element from a storage pool when remaining idle storage
    elements reside in the pool.

7.  Idle instance threshold:  a pre-determined idle instance count
    value signifying that too many instances of obtaining a storage
    element from a storage pool have observed remaining idle storage
    elements.

      The method comprimises two coordinating algorithms:  one for
obtaining storage elements for use; one for retiring storage elements
from use.  These algorithms presume an appropriate positive idle
instance threshold has been determined, and that an appropriate
positive storage pool threshold has been initialized.

Algorithm for obtaining a storage element for use:

1.  If the storage pool has no available idle storage elements then:

    o   Invoke an operating system service to allocate a storage
        element
    o   Increment the storage pool threshhold by one
    o   Exit this algorithm

2.  Remove an idle storage element from the storage pool for use.

3.  Decrement the storage pool size by one.

4.  If no remaining idle storage elements exist:

    o   Set the idle instance count to zero
    o   Exit this algorithm

5.  Increment the idle instance count by one.

Algorithm fo...