Scratch Pool Management Definition

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Scratch Pool Management Definition

The Scratch Pool Management feature lets you define the ranges or a subrange in the VMF as a scratch tape pool

Restrict output access to the pool based on the SMS Management Class, data set name, job name, and/or unit name.

When CA TLMS intercepts a scratch-pool-controlled nonspecific mount request, it modifies the text of the mount message. The name reflects the pool name instead of the SCRTCH or PRIVAT that the system generates when mounting a volume from the correct pool.

If a scratch-pool-controlled request is generated and the mounted volume is not in the correct range, CA TLMS demounts the invalid volume and reissues the mount request. If a nonpool controlled request is generated and the tape mounted is assigned to a scratch pool, it is demounted and the request reissued.

The READONLYnnnnn subpool definition is also allowed. If the first eight characters of the subpool name are READONLY (followed by any five characters), the tapes in that subpool can be opened for READ processing only. No output is allowed.

Note: Never point a CTONSMxx rule to a READONLYnnnnn subpool.

Use this function when:

You are testing a peer-to-peer (grid) configuration of a virtual tape system.
You do not want to allow updates to any production tapes while in Disaster Recovery.

Note: Do not suppress the IBM mount messages that CA TLMS uses to process through the MPF exit. These message IDs are IAT5210, IAT5624, IEC101A, IEC501A, IEC501E, IEF233A, IEF233D, IEC704A, IEC534D, and IEC507D. If they are suppressed, CA TLMS honors the suppression bit and the messages are not handled. If the mount messages are being suppressed, acratch subpooling does not function properly.

You can enable each scratch pool for Real-time Stacking. Because file stacking is done at the pool level, ensure that all files directed to a stacking subpool have common characteristics, such as retention, vaulting, and security. You can dynamically stack any file that is eligible for normal direction to a specific scratch pool onto a volume already containing active files. with three restrictions:

The label type must be SL.
The file is not temporary.
The file sequence is 1 (default) and a specific volume was not coded in the VOL=SER= field.

A volume can be stacked if it has other files that are dynamically stacked with a higher file sequence number and with a stacking enabled scratch subpool. The volume must meet the following restrictions:

Not marked as nonstackable
Not closed by abend
Not out-of-area
Not an EDM-controlled volume
Not part of a multivolume chain

If the next available volume is in use, it is bypassed and the next available volume is selected. TLMS does not delay a job waiting to be dynamically stacked.

Specification:

Control statements must be supplied in two members in CAI.CTAPOPTN.

CTOSCRxx describes the pool names and the range of tapes assigned.
CTONSMxx describes the SMS Management Class or combination of data set name, creating job name, and unit name that can access a pool that is defined in CTOSCRxx.

These two members are read during the CA Common Services TLMSRIM initialization of CA TLMS and their contents are verified before implementing the option.

Name Control Statement (CTOSCRxx)

The Name Control statement must be supplied in CTOSCRxx. The format is:

SCRPOOL=name,[STACK=YES/NO,]
[MAXFILES=nnnn,] [THRESHOLD=yyy,]
[SNEXT=SPECIFIC/SCRATCH,]
[NCAT=STACK/NEXT,]
RANGE=lowvol-highvol [,RANGE=lowvol-highvol]

SCRPOOL

Identifies the control statement and must be the first keyword.

name

The name that you assign to this scratch tape pool. The name can be up to 13 characters but must not contain a blank, comma, equal (=) sign, or single quote.

STACK=YES/NO

Indicates whether to activate file stacking for this pool.

MAXFILES=nnnn

Used if stacking is active for this pool. Specifies the maximum file sequence number that can be dynamically assigned at file open time. Values can be 1-9999. Default=200

THRESHOLD=nnn

Used if stacking is active for this pool. Specifies the volume use that, if reached during close processing, makes the volume no longer eligible for dynamic stacking. Values can be 1-100 and can reflect the percent of capacity that is used for the media type as identified in the VMF. Default=80

NCAT=STACK/NEXT

Used if stacking is active for this pool. Indicates what to do to files that do not have CATALOG specified as their normal disposition in the JCL. STACK indicates that these files are eligible like cataloged files. NEXT indicates that they are not eligible for file stacking (file sequence is 1). The SNEXT option is used.

SNEXT=SPECIFIC/SCRATCH

Used if stacking is active for this pool. Indicates what to do in all of the following cases:

NCAT=NEXT and the file does not have CATALOG in second disposition.
No eligible active volumes were found in pool to stack files on.

If SNEXT=SPECIFIC is specified, a specific VOLSER calls the next scratch tape in the pool. The scratch subpool is searched for the next volume in scratch status.

If SNEXT=SCRATCH is specified, a normal CTS002 message asks to mount a scratch tape from the specified pool.

RANGE=lowvol-highvol

Indicates the external volume serial number in the pool.

lovol: Lowest external volume serial number in the pool range
hivol: Highest external volume serial number in the pool range

The RANGE keywords must be the last keywords for the pool.

If either MAXFILES or THRESHOLD is reached, the volume is marked as "no longer eligible for stacking".

To continue a scratch pool definition statement, end the statement with a complete parameter followed by a comma, and continue on to the next statement beginning in position 1 or later. The number of continuations that are allowed has no limit, but only 255 ranges per tape pool are permitted.

You can name Scratch pools with any combination of up to 13 EBCDIC characters. Do not use a blank, comma, equal sign, or single quote. Because it appears in modified mount messages, make the name meaningful to the operator, as illustrated by the following examples:

SCRPOOL=100000-109999	Any tape with a volume serial number in	the
			 range of 100000 through 109999 
SCRPOOL=BLUE.STRAP	Tape with a blue strap 
SCRPOOL=1200.FOOT	Any 1200 foot tape reel 
SCRPOOL=POOL.A		Any tape from tape pool A 
SCRPOOL=CERTIFIED	Specially certified tape 
SCRPOOL=BACKUP.TAPE	Special backup-only tape pool 
SCRPOOL=SVC.DUMP	Pool for SVC dump tapes only

The choice of names is unlimited and can reflect your operating environment.

The members of a single tape pool do not need to be contiguous volumes in the tape library. Each tape pool can contain a number of ranges of volume serial numbers. However, a VOLSER cannot be specified in more than one subpool definition. For each range required, specify:

RANGE=lowvol-highvol

The values for lowvol and highvol can specify the same volume serial number, resulting in a single-volume tape pool.

Note: If STACK=YES and MAXFILES=1, then every scratch request within the pool follows the SNEXT keyword. If you use SNEXT=SPECIFIC, all scratch requests are turned into specific volser requests but no dynamic file stacking is performed.

Name Control Examples:

Example 1

SCRPOOL=SCRPOOL.A,RANGE=W10000-W10099,RANGE=Y09900-Y09999,
    RANGE=000000-009999

Example 2

SCRPOOL=000000-009999,RANGE=000000-009999

Example 3

SCRPOOL=BLUE,RANGE=X99000-X99099,RANGE=X89000-X89049

Example 4

SCRPOOL=STACKM,
    STACK=YES,THRESHOLD=70,
    RANGE=201000-202000

Example 5

SCRPOOL=100000-100099,RANGE=750003-750187

Examples 1 through 4 are correct examples, reflecting both the external nature of the scratch pool and its contents. Example 5 shows the type of error to avoid. The external description of the scratch pool implies a different set of volumes than the RANGE parameter defines.

To direct an output request to a specific scratch subpool using JCL, the pool name must be six characters or less. See Example 3. Code the pool name as if it were the VOLSER.

Note:

The unit that is specified must be able to satisfy at least one of the tapes from the specified pool.
You can specify only one pool name in the VOL=SER= field. You cannot add other VOLSERs except for the scratch subpool name.
You cannot have two or more DD statements in the same step pointing to the same scratch subpool through the VOL=SER= specification. You can have two or more DD statements using VOL=SER=poolid, but they must be different pool names.
```
//ddname   DD DSN=tape,dsname,DISP=(NEW,CATLG),UNIT=cart,
//         VOL=SER=BLUE,LABEL=(1,SL)
```

Assignment Control Statement (CTONSMxx)

To define scratch assignment rules, generate control statements specifying the poolname and either SMS Management Class or a combination of data set name, creating job name, and unit name. The format for the assignment control statement is:

DSN=dsname,JOB=jobname,POOL=poolname,UNIT=unitname

MGMTCLAS=classname,POOL=poolname

DSN: This assignment applies to only those data sets whose data set name is the specified dsname, unless further restricted by the JOB or UNIT parameter. If DSN is coded, MGMTCLAS cannot be specified. Code DSN=&&TEMP to assign temporary data sets or work tapes to scratch pools. The data set name can be fully qualified or you can use the CA TLMS Pattern Masking facility to specify it. For more information, see Pattern Masking.
JOB: This assignment applies only to data sets being created with the specified job name. If JOB is coded, MGMTCLAS cannot be coded. The job name can be qualified or specified using the CA TLMS Pattern Masking facility.
UNIT: This assignment specifies the unit physical name (ccuu). Esoteric names are not supported. If UNIT is coded, MGMTCLAS cannot be coded. The unit name can be qualified or specified using the CA TLMS Pattern Masking facility. Enter Three character units with a leading zero.
MGMTCLAS: This assignment specifies the 1-8 character SMS Management Class name. The SMS Management Class name cannot be coded using CA TLMS pattern masking specifications. If MGMTCLAS is coded, DSN, JOB, and UNIT cannot be coded.
POOL: Assignments that are made under this use tapes from the tape pool specified by poolname.

To continue a scratch pool assignment statement, end the statement with a comma before position 72 and continue on to the next statement, beginning in position 1 or later. The number of continuations that are allowed has no limit.

Important! If you change the production CTONSMxx member and REINIT CA TLMS to make them active, add the new entries to the very end of the current member for the real-time tape processing not to be affected.

Assignment Control Statement Examples:

To assign a data set to a tape pool every time the data set is created, enter:

DSN=dsname,POOL=poolname

Make this assignment regardless of the creating job or unit.

If local naming conventions call for backup data sets to have names of NIGHTLY.BACKUP.volser.generation, the nightly backups can be assigned to a specific pool by:

DSN=NIGHTLY.BACKUP.-,POOL=backup.pool

To use a special pool for IMS or CICS online log tapes:

DSN=ims.log.dsname,JOB=ims.jobname,POOL=ims.log.pool
DSN=cics.log.dsname,JOB=cics.jobname,POOL=cics.log.pool

If naming conventions require that all test jobs begin with a character, such as a T, you can restrict programmer test tapes to a specific range by entering:

DSN=-,JOB=T-,POOL=test.poolname

Assignment is made by determining whether the combination of dsname and job name matches any of the entries read during the initialization. For multiple matches, such as:

DSN=ABCD-,POOL=C,UNIT=0E8?
DSN=ABC-,POOL=D,UNIT=0E??

A data set named ABCDE is assigned to pool C, because ABCD- is a more qualified match than ABC-. For two equal matches on a data set name, use the entry with the more exact job name or unit name or both.