Question & Answer
Question
Display of device status shows allocated to MASTER ASID 0000; unable to bring device offline.
Cause
Device contains LNKLST data sets allocated at IPL/NIP
Answer
Description:
When it is necessary to bring a non-sysres DASD device offline for maintenance and that device had been allocated at NIP time because it contained system data sets, it may appear as allocated to *MASTER* and ASID 0000. The system data sets for which it was allocated typically are for the LNKLST concatenation. A VARY OFFLINE of this device marks it pending offline. In releases prior to z/OS 1.8 attempts to bring the device completely offline will fail even if the following steps are followed (see note on release 1.8 below):
1. creating a new LNKLST set without the data sets
2. activating this new LNKLST set
3. updating LLA so it does not manage the data sets any longer
4. using LNKLST UPDATE so that no jobs use a LNKLST that
contained the data sets
This is due to the technique used to allocate and access LNKLST
data sets at IPL/NIP. At present no clean way to get these data
sets unallocated exists. Historically, these types of data sets
were to be placed on sysres and bringing that volume offline
would never be an option.
An IPL may be required to get the device offline. The UCBALOC
indicator in the device UCB causes the device to remain online;
since there is no way to cause the device to become unallocated
by all users after IPL/NIP has completed, no operational
procedure exists to bring the device offline.
At z/OS 1.8 and above, volumes containing LINKLIST datasets
can be successfully varied offline after deleting ALL the
volume's LINKLIST datasets from ALL LNKLST sets (Current and
Active LNKLST sets). The following commands can be used to
create a new LNKLST set without the volume's LNKLST datasets
and then forcing all jobs to use the new LNKLST:
SETPROG LNKLST,DEFINE,NAME=newlnklstset,COPYFROM=oldlnklstset
SETPROG LNKLST,DELETE,NAME=newlnklstset,DSNAME=volumelnklstds1
SETPROG LNKLST,DELETE,NAME=newlnklstset,DSNAME=volumelnklstds2
SETPROG LNKLST,DELETE,NAME=newlnklstset,DSNAME=volumelnklstds3
.
.
.
SETPROG LNKLST,DELETE,NAME=newlnklstset,DSNAME=volumelnklstdsx
SETPROG LNKLST,ACTIVATE,NAME=newlnklstset
SETPROG LNKLST,UPDATE,JOB(*)
P LLA
S LLA,SUB=MSTR,LLA=xx
For more information on the SETPROG command, see:
z/OS MVS Initialization and Tuning Reference
Additional Symptoms:
Device pending offline
When it is necessary to bring a non-sysres DASD device offline for maintenance and that device had been allocated at NIP time because it contained system data sets, it may appear as allocated to *MASTER* and ASID 0000. The system data sets for which it was allocated typically are for the LNKLST concatenation. A VARY OFFLINE of this device marks it pending offline. In releases prior to z/OS 1.8 attempts to bring the device completely offline will fail even if the following steps are followed (see note on release 1.8 below):
1. creating a new LNKLST set without the data sets
2. activating this new LNKLST set
3. updating LLA so it does not manage the data sets any longer
4. using LNKLST UPDATE so that no jobs use a LNKLST that
contained the data sets
This is due to the technique used to allocate and access LNKLST
data sets at IPL/NIP. At present no clean way to get these data
sets unallocated exists. Historically, these types of data sets
were to be placed on sysres and bringing that volume offline
would never be an option.
An IPL may be required to get the device offline. The UCBALOC
indicator in the device UCB causes the device to remain online;
since there is no way to cause the device to become unallocated
by all users after IPL/NIP has completed, no operational
procedure exists to bring the device offline.
At z/OS 1.8 and above, volumes containing LINKLIST datasets
can be successfully varied offline after deleting ALL the
volume's LINKLIST datasets from ALL LNKLST sets (Current and
Active LNKLST sets). The following commands can be used to
create a new LNKLST set without the volume's LNKLST datasets
and then forcing all jobs to use the new LNKLST:
SETPROG LNKLST,DEFINE,NAME=newlnklstset,COPYFROM=oldlnklstset
SETPROG LNKLST,DELETE,NAME=newlnklstset,DSNAME=volumelnklstds1
SETPROG LNKLST,DELETE,NAME=newlnklstset,DSNAME=volumelnklstds2
SETPROG LNKLST,DELETE,NAME=newlnklstset,DSNAME=volumelnklstds3
.
.
.
SETPROG LNKLST,DELETE,NAME=newlnklstset,DSNAME=volumelnklstdsx
SETPROG LNKLST,ACTIVATE,NAME=newlnklstset
SETPROG LNKLST,UPDATE,JOB(*)
P LLA
S LLA,SUB=MSTR,LLA=xx
For more information on the SETPROG command, see:
z/OS MVS Initialization and Tuning Reference
Additional Symptoms:
Device pending offline
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Document Information
Modified date:
03 September 2021
UID
isg3T1000089