Age of DSN.

rahulbank · Posted: Thu Jan 29, 2009 1:25 am

I understand that we mean the age of DSN as the no. of days elapsed between referenced and today. WHat is the concept when it gets migrated to the tape say ML2 will it again start with AGE 0 there. My problem is I am able to generate a list of dsn's migrated and recalled with in one day or two but wanted to cross check with this.

ALso when a dsn gets recalled do we see an age parameter there(as we see in the case of migrate).

Thanks for Reading

expat · Posted: Thu Jan 29, 2009 12:18 pm

After 20+ years of storage management, I have always understood the age of a dataset to be the number of days since it was created, not the number of days since it was last accessed.

The number of days that a dataset is permitted to reside on any particular storage level, ML0, ML1 or ML2 is usually defined by the SMS ACS routines.

The fact that these datasets are migrated and then recalled in a short time frame suggests either back luck, or more likely SMS ACS routines that require a little maintenence.

To get a better understanding of how it all works I would speak to your storage people who will know all of the site specific information.

rahulbank · Posted: Sat Jan 31, 2009 2:56 pm

Thanks for the reply.

The age I was referring to here was the age = no. which appears when migrating a file .... in this case also does age = parameter reflect the age since it was created...

expat · Posted: Sat Jan 31, 2009 3:12 pm

The parameters for dataset migration are setup by your storage management people, and it is them that determine these parameters.

The age of a dataset may be one of the parameters used, along with the number of days since last access, or the size of a dataset, or the organisation of a dataset.

As far as I am concerned the age of a dataset is the number of days since it was created.

Please show an example of the messages and codes being issued that seem to cause you some concern.

rahulbank · Posted: Sat Jan 31, 2009 11:47 pm

I am also one of the storage persons for my shop...Actually I am trying to generate a list of dsn's which have been migrated and then recalled in two days...when I was researching on the same I came across a code which coluld do so...but i was wondering when a dsn is getting recalled it is not accompanied by a "age" parameter so wanted to cross check this for my own desire to know more about storage....

And now see this example in which age = todays(31) - refernced date(26) =5 as it says in the space mgmt

THC.$IOSYM TCP423
30 76 1 3390 PO U 0 0 2008/11/19 2009/01/26

This dsn created on 11/19 and got referred on 01/26...

AT 11:38:41 ON 2009/01/31,
ACTION=SPCMGMT FRVOL=TCP423 TOVOL= *** TRACKS= 0 RC= 99, REASON= 6, AGE= 5, DSN=THC.$IOSYM

expat · Posted: Tue Feb 03, 2009 12:18 pm

For a definitive explanation, my only suggestion would be to check out the message code issued against the manual for what the IBM explanation is.