Effects of DFSMStvs, log stream, and data set states

These tables describe the effects of the DFSMStvs states, log stream states, and data set states on DFSMStvs processing.

You can use the VARY SMS command to change the state of DFSMStvs, log streams that DFSMStvs uses, and data sets that DFSMStvs processes.

Recommendation: Be careful about quiesce with a path name; always use a base name.

Related reading: For information about the VARY SMS command, see z/OS MVS JCL Reference.

Table 1 describes the effects of the states of a DFSMStvs instance.

Table 1. Effects of DFSMStvs states on DFSMStvs processing
DFSMStvs state	Effect
Initializing	DFSMStvs is in the process of coming up and cannot accept any work until it has completed this process.
Active	DFSMStvs is fully initialized and is accepting work. It is possible for DFSMStvs to be in the active state while it is still completing restart processing.
Quiescing	DFSMStvs is in the process of completing any units of recovery that were in progress when the quiesce occurred but will not accept any new ones. DFSMStvs transitions from quiescing to quiesced when all in-progress units of recovery are completed and all data sets that are open in DFSMStvs mode are closed.
Quiesced	DFSMStvs has completed all units of recovery that were in progress when the quiesce occurred, and there are no active DFSMStvs opens. DFSMStvs does not accept any work until it is enabled.
Disabling	DFSMStvs is not accepting any requests. DFSMStvs transitions from disabling to disabled when all data sets that are open in DFSMStvs mode are closed.
Disabled	DFSMStvs is not accepting any requests, and all data sets that were open in DFSMStvs mode have been closed. DFSMStvs does not accept any new work until it is enabled.

Table 2 describes the effects of undo log states, shunt log states, log-of-log states, and forward recovery log states.

Table 2. Effects of log states on DFSMStvs processing
Log type	Log state	Effect
Undo or shunt	Enabled	DFSMStvs services are available for use both by in-progress units of recovery and new units of recovery.
Undo or shunt	Quiescing	DFSMStvs allows requests by existing units of recovery to be processed but does not allow new units of recovery to start. Quiescing the undo or shunt log is equivalent to quiescing DFSMStvs.
Undo or shunt	Quiesced	There are no units of recovery using DFSMStvs services and new units of recovery cannot start
Undo or shunt	Disabling	All DFSMStvs requests are failed, including those submitted by in-progress units of recovery. Units of recovery are neither committed nor backed out and cannot be completed until DFSMStvs restart processing is run. Disabling the undo or shunt log is equivalent to disabling DFSMStvs.
Undo or shunt	Disabled	There are no units of recovery using DFSMStvs services and new units of recovery cannot start. All data sets that were open for DFSMStvs processing have been closed, and DFSMStvs has unregistered with RRS and the lock manager and disconnected from its logs.
Log of logs	Enabled	DFSMStvs writes tie-up records and file-close records to the log of logs so that they can be used to optimize forward recovery processing.
Log of logs	Quiescing	DFSMStvs writes file-close records to the log of logs for any forward recoverable data sets that are currently open but does not write any additional tie up records to the log of logs.
Log of logs	Quiesced	All paired tie-up records and file-close records were written to the log of logs, but no additional records are being written to the log of logs.
Log of logs	Disabling	DFSMStvs runs without the log of logs. If forward recovery is needed for any forward recoverable data sets, the forward recovery utility will not be able to use the optimization provided by the log of logs.
Log of logs	Disabled	DFSMStvs runs without the log of logs. If forward recovery is needed for any forward recoverable data sets, the forward recovery utility will not be able to use the optimization provided by the log of logs. All data sets that had written tie up records to the log of logs have been closed.
Forward recovery	Enabled	DFSMStvs allows data sets that use the forward recovery log to be opened and processed.
Forward recovery	Quiescing	DFSMStvs allows all jobs that are using the forward recovery log to continue processing but does not allow any new opens of data sets that use the forward recovery log.
Forward recovery	Quiesced	There are no jobs that have data sets that use the forward recovery log open, and DFSMStvs does not allow any new opens of data sets that use the forward recovery log.
Forward recovery	Disabling	DFSMStvs fails any requests that need to write to the forward recovery log, which causes logging failures in jobs that had data sets open that use it. Because no further records can be written to the forward recovery log, units of recovery that were in progress and using it can be neither committed nor backed out. They are shunted and must be either purged or manually retried when the forward recovery log is later enabled.
Forward recovery	Disabled	All data sets that had been using the forward recovery log have been closed. Any open that requires the use of the forward recovery log will be failed.

Table 3 describes the effects of data set states.

Table 3. Effects of data set states on DFSMStvs processing
Data set state	Effect
Not quiesced	The data set is available for normal use.
Quiescing	VSAM RLS allows those jobs that were using the data set to continue using it but does not allow additional opens.
Quiesced	The data set is not open for either RLS or DFSMStvs access and cannot be opened for RLS or DFSMStvs access until it is unquiesced.
Quiescing for copy	DFSMStvs allows any units of recovery that had previously updated the data set (or issued a GET UPD) to continue using the data set. It will also allow both new and in-progress units of recovery to read the data set, but it will not allow any unit of recovery that had not previously updated the data set (or issued a GET UPD) to issue GET UPD, PUT, or ERASE against the data set.
Quiesced for copy	There are no units of recovery that have updated the data set (or issued a GET UPD), and DFSMStvs will not allow any unit of recovery to issue GET UPD, PUT, or ERASE against the data set. Units of recovery can read the data set.
Quiesced for backup-while-open (BWO)	DFSMStvs ensures the writing of any log records required to enable forward recovery of the sphere from the backup copy that is about to be taken. DFSMStvs also writes a record to indicate that it received a QUIBWO. The sphere remains open and normal processing of the data set is allowed.