Gadi, Mike has a good point.  Doing HSM tape recycles could help free up any 
tapes with a low number of datasets on them.  This is true for migration tapes 
and backup tapes.  Be warned that if you don't do tape recycles on a scheduled 
basis the process could possibly run for a long time.  As an example, I think 
that could then impact HSM process of recalls from tape.  I believe the place I 
last worked at did tape recycles every day.

Also, I should have mentioned the information I pasted in my earlier reply came 
from the "DFSMSdfp Storage Administration" manual for z/OS 2.5.  It can be 
found in "Chapter 8. Defining management classes".


Paul

-----Original Message-----
From: IBM Mainframe Discussion List <[email protected]> On Behalf Of 
Mike Schwab
Sent: Wednesday, March 13, 2024 1:30 PM
To: [email protected]
Subject: Re: What happens in HSM when I change a Management Class

You should be recycling tapes with a low percent of active datasets.
This copies the remaining active datasets to a new tape then marking this on as 
inactive.  You can manually issue a recycle command against a specific volume.

On Wed, Mar 13, 2024 at 10:56 AM Gadi Ben-Avi <[email protected]> wrote:
>
> Hi Paul,
> Thanks for your detailed explanation.
>
> I would like to delete extra copies of backups, backups that have been on HSM 
> for more than a specified number of days, and as a result of that, tapes that 
> become empty will be deleted.
>
> The end result would be that every backed-up dataset that still exists could 
> have more than one backup, and datasets that do not exist anymore would have 
> only one backup.
>
> Gadi
> ________________________________
> From: IBM Mainframe Discussion List <[email protected]> on 
> behalf of Paul Feller <[email protected]>
> Sent: Wednesday, March 13, 2024 16:09
> To: [email protected] <[email protected]>
> Subject: Re: What happens in HSM when I change a Management Class
>
> [You don't often get email from 
> [email protected]. Learn why this is 
> important at https://aka.ms/LearnAboutSenderIdentification ]
>
> Gadi, I have to ask.  Are trying to delete backups of individual 
> datasets or the actual tapes created during dataset backup processing?
>
> If you are trying to manage the actual backups of individual datasets, 
> have you looked at the different management classes used for the datasets?
>
> The following fields in the management class affect backups taken for 
> an individual dataset.
>
> Retain Days Only Backup Ver:
>  Indicates how many days to keep the most recent backup version of a 
> deleted data set, starting from the day DFSMShsm detects it has been 
> deleted. This attribute applies only when a data set no longer exists 
> on primary (level 0) or migrated (levels 1 and 2) storage. The default 
> is 60. This field does not apply to objects. Backup copies of objects 
> are not retained when the original object is deleted.
>
> Retain Days Extra Backup Vers:
>  Indicates how many days to keep backup versions other than the most 
> recent one, starting from the day backups were created. It applies 
> only when more than one backup version exists, and when a data set has 
> low activity. This attribute applies whether the data set has been 
> deleted or not. The default is 30. The number of extra versions is the 
> number of backup versions minus one. If you specify 1 for Number of 
> Backup Vers, there are no extra versions. For example, if you specify 
> 3 for Number of Backup Vers (Data Set Deleted), the number of "extra" 
> versions for deleted data sets is 2. These 2 versions are managed 
> according to the Retain Days Extra Backup Vers attribute. Any other 
> versions that may have existed when the data set was deleted will be deleted 
> the next time EXPIREBV is processed.
>
> Number of Backup Vers:
>  Specifies the maximum number of backup versions to retain for a data set.
> The default is 2 if the data set still exists and 1 if it has been deleted.
>  Creating a new backup version when the number of backup versions 
> already equals the value specified for the appropriate Number of 
> Backup Vers attribute (Data Set Exists) causes the oldest version of 
> the appropriate type to be deleted.
>  The number of backup versions is used to determine whether OAM should 
> write one or two backup copies of the objects, when you activate the 
> SECONDBACKUPGROUP function for objects using SETOSMC in the CBROAMxx 
> member of PARMLIB. If the number of backup versions is greater than 1 
> and AUTO BACKUP is Y, OAM will create two backup copies. When the 
> original object is expired or deleted, all backup copies are also deleted.
>
>
>
> Paul
>
> -----Original Message-----
> From: IBM Mainframe Discussion List <[email protected]> On 
> Behalf Of Gadi Ben-Avi
> Sent: Wednesday, March 13, 2024 6:54 AM
> To: [email protected]
> Subject: Re: What happens in HSM when I change a Management Class
>
> Thanks
>
> -----Original Message-----
> From: IBM Mainframe Discussion List <[email protected]> On 
> Behalf Of Mark Jacobs
> Sent: יום ד 13 מרץ 2024 13:43
> To: [email protected]
> Subject: Re: What happens in HSM when I change a Management Class
>
> [You don't often get email from
> [email protected]. Learn why this is 
> important at https://aka.ms/LearnAboutSenderIdentification ]
>
> I believe it'll take affect during your secondary space management cycle.
>
> Mark Jacobs
>
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>
> On Wednesday, March 13th, 2024 at 6:46 AM, Gadi Ben-Avi 
> <[email protected]>
> wrote:
>
> > Hi
> > when reviewing our HSM configuration we found that the management 
> > class
> used for all SMS backups says:
> >
> > Expire after Days Non-usage . . NOLIMIT (1 to 93000 or NOLIMIT) 
> > Expire after Date/Days . . . . . NOLIMIT (0 to 93000, yyyy/mm/dd or
> > NOLIMIT)
> >
> > Retention Limit . . . . . . . . . NOLIMIT (0 to 93000 or NOLIMIT)
> >
> > As I understand it, this means that backups will remain forever.
> >
> > If I change the values, will HSM start deleting backups?
> > Will it happen immediately, during nightly processing or do I have 
> > to tell
> HSM to do it?
> >
> > Gadi
> >
> > --------------------------------------------------------------------
> > -- For IBM-MAIN subscribe / signoff / archive access instructions, 
> > send email to [email protected] with the message: INFO 
> > IBM-MAIN
>
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--
Mike A Schwab, Springfield IL USA
Where do Forest Rangers go to get away from it all?

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