Manually reclaiming storage is a hassle. Wouldn't you rather automate that process?

Every now and again, a System i administrator should run the Reclaim Storage (RCLSTG) command on the system. If you've got limited experience with the platform, the system, or even the command itself, then you may not be aware of what it does and how best to schedule it.

Why Should I Run a RCLSTG? 

Look at the RCLSTG as a "spring cleaning" for your system. The process checks the headers and pointers on all objects in the Auxiliary Storage Pool (ASP) and attempts to validate and reclaim orphaned, damaged, and incorrectly updated objects.

As the RCLSTG command also deletes unusable objects or fragments, it's especially relevant after a sudden power failure or system crash.

How Long Will It Take to Run? 

This is very difficult to estimate, but probably the best way is to check how long it ran the last time. Display the data area QUSRSYS/QRCLSTG using this command:

DSPDTAARA DTAARA(QUSRSYS/QRCLSTG)

Figure 1: Determine how long RCLSTG ran.

Our example shows that the last RCLSTG ran from 1740 to 1911 (5:40 p.m. to 7:11 p.m.) on February 9, 2009.

What Preparation Should I Undertake?

As the RCLSTG could (albeit unlikely) impact the day-to-day running of the system, it's advisable to perform a full system backup and if possible an IPL prior to running the command.

How Do I Run a RCLSTG? 

You'll need to sign on using a QSECOFR profile or an equivalent profile before bringing the system to a restricted state (all jobs need to be ended apart from the system console). After ensuring that all users have signed off and that all batch processes are complete, a restricted state can be achieved by using this command:

 ENDSBS SBS(*ALL) OPTION(*IMMED)

The system is in a restricted state when you see the CPF0968 message on the QSYSOPR message queue.

Figure 2: CPF0968  indicates that the system is in a restricted state.

Once the system is ready, issue this command:

RCLSTG

Of course, the process described is very manual and somewhat dated, so why not schedule the whole process using Halcyon's Restricted Task Manager? It's so simple!

Decide when you want to run it.

Figure 3: Choose when to run RCLSTG.

Then decide how you'd like to achieve a restricted state--by automatically notifying the online users or not.

Figure 4: Choose how to achieve a restricted state.

Next, decide what you want to run--in our example, a SAVSYS, *NONSYS, SAVDLO, and a SAV followed by RCLSTG, all with built-in error recovery and Short Message Service (SMS) task-completion capabilities.

Figure 5: Choose what you want to run.

Post-RCLSTG Checks

1.  Informational status messages will be sent to the session running the RCLSTG, but it's good practice to check the QSYSOPR message queue for any anomalies when RCLSTG completes. 

2.  Any objects found to be secured by damaged or missing authorization lists are assigned to the QRCLAUTL authorization and should be reviewed by using the command DSPAUTLOBJ AUTL(QRCLAUTL).

3.  Check for any objects discovered that are owned by a damaged or deleted user profile or any objects that have no owners as assigned to QDFTOWN. These objects can be reviewed by using the command WRKOBJOWN USRPRF(QDFTOWN).

4.  Any objects that are lost from their original specified location are placed in QRCL for qsys.lib objects and /QReclaim or /QOpenSys/QReclaim for IFS objects. Review these by using the commands below:

DSPLIB LIB(QRCL)

WRKLNK OBJ('/QOpenSys/QReclaim')

WRKLNK OBJ('/QReclaim')

Automatically reclaiming storage is easy and painless with Halcyon's Restricted Task Manager. Eliminate the hassles of manual storage reclamation!

With more than 25 years of experience in the IT industry and coming from an operational background, Ash Giddings is a technically astute Product Manager. He has worked for some of the largest data centers in Europe and in the U.S. has advised large companies on major projects to save costs and improve efficiencies. He began his career on IBM Mainframe before moving onto midrange systems such as IBM i and AIX and then Windows and Linux. His technical background has enabled him to find solutions for challenging IT problems.

 

Ash is a regular speaker at international conferences and industry events.