CATALOG RECOVERY THROUGH SYSTEM MANAGEMENT FACILITIES REVERSE TRANSVERSAL

• US 20100077255A1
• Filed: 09/22/2008
• Published: 03/25/2010
• Est. Priority Date: 09/22/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Reed, David Charles, Smith, Max Douglas, McCune, Franklin Emmert, Lehr, Douglas Lee
• Granted Patent: US 8,024,519 B2
• Time in Patent Office: Days
• US Class Current: 714/16
• CPC Class Codes: G06F 11/1435 using file system or storage system metadata

Abstract

A method for forward recovery of a catalog of a data storage system, comprising providing a recovery catalog and SMF records. In reverse chronological order, the (i)th entry of the record is checked for a data set change command. If none, the next entry is examined. Otherwise, the (j)th data set is identified and checked for inclusion in the recovery catalog. If it already is, the next entry is selected. If not, a data set location record is added. This process is repeated for each entry in the SMF record. Next, a (h)th data set on the (k)th volume is selected and checked for inclusion in the recovery catalog. If that (h)th data set has been added to the recovery catalog, a next data set is selected. Otherwise, a data set location record for the (h)th data set is added. The process is repeated for each data set on each volume.

Claims

1. A method for forward recovery of a catalog for a data storage system comprising a plurality of data sets encoded in a plurality of volumes, comprising:

examining system management facilities (“

SMF”

) records to identify datasets recited therein;

adding to a recovery catalog one or more datasets identified in said SMF records;

reviewing seriatim each of said plurality of volumes;

identifying any additional datasets encoded in said plurality of volumes, wherein said additional datasets were not recited in said SMF records;

adding said additional datasets to said recovery catalog.

2. The method of claim 1, wherein said plurality of datasets comprise (N) data sets encoded in (P) volumes, wherein (N) and (P) are greater than or equal to 1, wherein said examining further comprises:

retrieving said SMF records, wherein said SMF records comprises (M) entries, wherein (M) is greater than or equal to 1;

choosing an (i)th SMF entry, wherein said (i)th SMF entry comprises the most recent SMF entry, wherein (i) is initially set to 1, and wherein (i) is less than or equal to (M);

determining if an (i)th SMF entry comprises a data set change command;

operative if said (i)th SMF entry does not comprise a data set change command, incrementing (i) by unity;

operative if said (i)th SMF entry comprises a data set change command;

identifying a (j)th data set recited in said (i)th SMF entry;

ascertaining if said (j)th data set is recited in said recovery catalog;

operative if said (j)th data set is recited in said recovery catalog, incrementing (i) by unity; and

operative if said (j)th data set is not recited in said recovery catalog, adding to said recovery catalog a data set location record reciting a storage address for said (j)th data set and increment (i) by unity;

establishing if (i) is greater than (M);

operative if (i) is not greater than (M), repeating said selecting, said determining, said identifying, and said ascertaining.

3. The method of claim 2, wherein said reviewing step further comprises:

choosing a (k)th volume, wherein the (k)th volume comprises (Z) datasets, and wherein (Z) is greater than or equal to 1 and less than or equal to (N), and wherein (k) is initially set to 1;

selecting a (h)th data set located on the (k)th volume, wherein (h) is initially set to 1, and wherein (h) is greater than or equal to 1 and less than or equal to (Z);

verifying if said (h)th data set is recited in said recovery catalog;

operative if said (h)th data set is recited in said recovery catalog, increment (h) by unity;

operative if said (h)th data set is not recited in said recovery catalog, adding to said recovery catalog a data set location record reciting a storage address for said (h)th data set and incrementing (h) by unity;

determining if (h) is greater than (Z);

operative if (h) is greater than (Z);

incrementing (k) by unity;

assessing if (k) is greater than (P); and

operative if (k) is not greater than (P), setting (h) to 1 and repeating said electing, said verifying, said resolving; and

operative if (h) is not greater than (Z), repeating said verifying, said resolving, and said assessing.

4. The method of claim 2, wherein said identifying further comprises:

detecting a qualifier of the (j)th data set wherein said qualifier indicates whether a data set location record for the (j)th data set is to be included in said recovery catalog; and

operative if said qualifier indicates the location pointer is not to be included in said recovery catalog, incrementing (i) by unity and repeating said selecting, said determining, and said identifying.

5. The method of claim 3, wherein said selecting further comprises:

detecting a qualifier of the (h)th data set wherein said qualifier indicates whether a data set location record for the (h)th data set is to be included in said recovery catalog; and

operative if said qualifier indicates the location pointer is not to be included in said recovery catalog, incrementing (h) by unity and repeat said selecting electing.

6. The method of claim 3, wherein said (h)th data set is selected from a volume table of contents (“

VTOC”

) located on the (k)th volume.

7. The method of claim 3, wherein said (h)th data set is selected from a Virtual Sequence Access Method (“

VSAM”

) Volume Data Set (“

VVDS”

) located on the (k)th volume.

8. The method of claim 7, further comprising:

checking if said VVDS comprises a reverse pointer indicating that a catalog being replaced by said recovery catalog contained a location pointer to said VVDS; and

operative if said VVDS does not comprise said reverse pointer, incrementing (k) by unity and repeating said choosing and said electing.

9. A computer program product encoded in a computer readable medium and useable with a programmable computer processor to generate a recovery catalog for a data storage system comprising a plurality of data sets encoded in a plurality of volumes, the computer program product comprising:

computer readable program code which causes said programmable processor to generate a recovery catalog;

computer readable program code which causes said programmable processor to examine system management facilities (“

SMF”

) records to identify datasets recited therein;

computer readable program code which causes said programmable processor to add one or more datasets identified in said SMF records to said recovery catalog;

computer readable program code which causes said programmable processor to review seriatim each of said plurality of volumes;

computer readable program code which causes said programmable processor to identify additional datasets encoded in said plurality of volumes, wherein said additional datasets were not recited in said SMF records;

computer readable program code which causes said programmable processor to add said additional datasets to said recovery catalog.

10. The computer program product of claim 9, wherein said plurality of datasets comprise (N) data sets encoded in (P) volumes, wherein (N) and (P) are greater than or equal to 1, wherein said computer readable program code which causes said programmable processor to examine system management facilities (“

SMF”

) records further comprises;

computer readable program code which causes said programmable processor to retrieve said SMF records, wherein said SMF records comprises (M) entries, wherein (M) is greater than or equal to 1;

computer readable program code which causes said programmable processor to select an (i)th SMF entry, wherein said (i)th SMF entry comprises the most recent SMF entry, and wherein (i) is initially set to 1 and is less than or equal to (M);

computer readable program code which causes said programmable processor to determine if said (i)th SMF entry comprises a data set change command;

computer readable program code which, if said (i)th SMF entry does not comprise a data set change command, causes said programmable processor to increment (i) by unity;

computer readable program code which, if said (i)th SMF entry comprises a data set change command, causes said programmable processor to;

identify an (j)th data set, wherein (j) is greater than or equal to 1 and less than or equal to (N);

ascertain if said (j)th data set is recited in said recovery catalog;

computer readable program code which, if said (j)th data set is recited in said recovery catalog, causes said programmable processor to increment (i) by unity; and

computer readable program code which, if said (j)th data set is not recited in said recovery catalog, causes said programmable processor to add to said recovery catalog a data set location record reciting a storage address for said (j)th data set and increments (i) by unity.

11. The computer program product of claim 10, wherein said computer readable program code which causes said programmable processor to review seriatim each of said plurality of volumes further comprises:

computer readable program code which causes said programmable processor to choose a (k)th volume, wherein the (k)th volume comprises (Z) datasets, and wherein (Z) is greater than or equal to 1 and less than or equal to (N), and wherein (k) is initially set to 1;

computer readable program code which causes said programmable processor to select a (h)th data set located on the (k)th volume, wherein (h) is initially set to 1 and wherein (h) is greater than or equal to 1 and less than or equal to (Z);

computer readable program code which causes said programmable processor to determine if said (h)th data set is recited in said recovery catalog;

computer readable program code which, if said (h)th data set is recited in said recovery catalog, causes said programmable processor to increment (h) by unity;

computer readable program code which, if said (h)th data set is not recited in said recovery catalog, causes said programmable processor to add to said recovery catalog a data set location record reciting a storage address for said (h)th data set and increments (h) by unity.

12. The computer program product of claim 10, wherein said computer readable program code which causes said programmable processor to identify an (j)th data set, further comprises:

computer readable program code which causes said programmable processor to detect a qualifier of the (j)th data set wherein said qualifier indicates whether a data set location record for the (j)th data set is to be included in said recovery catalog.

13. The computer program product of claim 11, wherein said computer readable program code which causes said programmable processor to select an (h)th dataset further comprises:

computer readable program code which causes said programmable processor to detect a qualifier of the (h)th data set wherein said qualifier indicates whether a data set location record for the (h)th data set is to be included in said recovery catalog.

14. The computer program product of claim 11, wherein said computer readable program code which causes said programmable processor to select a (h)th data set further comprises computer readable program code which causes said programmable processor to select a (h)th data set from a volume table of contents (“

VTOC”

) located on the (k)th volume.

15. The computer program product of claim 11, wherein said computer readable program code which causes said programmable processor to select a (h)th data set further comprises computer readable program code which causes said programmable processor to select a (h)th data set from a Virtual Sequence Access Method (“

VSAM”

) Volume Data Set (“

VVDS”

) located on the (k)th volume.

16. The computer program product of claim 15, further comprising:

computer readable program code which causes said programmable processor to determine if said VVDS comprises a reverse pointer indicating that a catalog being replaced by said recovery catalog contained a location pointer to said VVDS.

17. The computer program product as defined in claim 16, wherein said computer readable program code which causes said programmable processor to select a (k)th volume further comprises computer readable program code which causes said programmable processor to select a (k)th volume based on a characteristic.

18. An article of manufacture comprising a computer readable medium comprising computer readable program code disposed therein to generate a recovery catalog for a data storage system comprising a plurality of data sets encoded in a plurality of volumes, the computer readable program code comprising a series of computer readable program steps to effect:

examining system management facilities (“

SMF”

) records to identify datasets recited therein;

adding one or more datasets identified in said SMF records to a recovery catalog;

reviewing seriatim each of said plurality of volumes;

identifying additional datasets encoded in said plurality of volumes, wherein said additional datasets were not recited in said SMF records;

adding said additional datasets to said recovery catalog.

19. The article of manufacture of claim 18, wherein said data storage system comprises (N) data sets encoded in (P) volumes, wherein (N) and (P) are greater than or equal to 1, wherein said computer readable program code to examine system management facilities further comprising a series of computer readable program steps to effect:

retrieving said SMF records, wherein said SMF records comprise (M) entries, wherein (M) is greater than or equal to 1;

selecting an (i)th SMF entry, wherein said (i)th SMF entry comprises the most recent SMF entry, wherein (i) is initially set to 1, and wherein (i) is less than or equal to (M);

determining if said (i)th SMF entry comprises a data set change command;

operative if said (i)th SMF entry does not comprise a data set change command, increment (i) by unity;

operative if said (i)th SMF entry comprises a data set change command;

identifying an (j)th data set, wherein (j) is greater than or equal to 1 and less than or equal to (N);

ascertaining if said (j)th data set is recited in said recovery catalog;

operative if said (j)th data set is recited in said recovery catalog, increment (i) by unity; and

operative if said (j)th data set is not recited in said recovery catalog, adding to said recovery catalog a data set location record reciting a storage address for said (j)th data set and increment (i) by unity.

20. The article of manufacture of claim 19, wherein said computer readable program code to review seriatim each of said plurality of volumes further comprising a series of computer readable program steps to effect:

choosing a (k)th volume, wherein the (k)th volume comprises (Z) datasets, and wherein (Z) is greater than or equal to 1 and less than or equal to (N), and wherein (k) is initially set to 1;

selecting a (h)th data set located on the (k)th volume, wherein (h) is initially set to 1, and wherein (h) is greater than or equal to 1 and less than or equal to (Z);

determining if said (h)th data set is recited in said recovery catalog;

operative if said (h)th data set is recited in said recovery catalog, increment (h) by unity,

operative if said (h)th data set is not recited in said recovery catalog, adding to said recovery catalog a data set location record reciting a storage address for said (h)th data set and increment (h) by unity.

21. The data storage system as defined in claim 19, wherein said computer readable program code for identifying a (j)th dataset further comprises a series of computer readable program steps to effect:

detecting a qualifier of the (j)th data set wherein said qualifier indicates whether a data set location record for the (j)th data set is to be included in said recovery catalog.

22. The data storage system as defined in claim 20, wherein said computer readable program code for selecting a (h)th dataset further comprises a series of computer readable program steps to effect:

detecting a qualifier of the (h)th data set wherein said qualifier indicates whether a data set location record for the (h)th data set is to be included in said recovery catalog.

23. The data storage system as defined in claim 20, wherein said computer readable program code for selecting a (h)th dataset further comprises a series of computer readable program steps to effect selecting said (h)th dataset from a volume table of contents (“

VTOC”

) located on the (k)th volume.

24. The data storage system as defined in claim 20, wherein said computer readable program code for selecting a (h)th dataset further comprises a series of computer readable program steps to effect selecting said (h)th dataset from a Virtual Sequence Access Method (“

VSAM”

) Volume Data Set (“

VVDS”

) located on the (k)th volume.

25. The data storage system as defined in claim 24, wherein said computer readable program code further comprises a series of computer readable program steps to effect detecting if said VVDS comprises a reverse pointer indicating that a catalog being replaced by said recovery catalog contained a location pointer to said VVDS.