iCan Blog Archive

It’s tough to make the new release highlights list. A valuable capability that will help reduce planned outages that didn’t make the cut for IBM i 7.1 announcement highlights is the capability to remove disk units from the partition without requiring an IPL or going into restricted state. While it’s documented in the Knowledge Center, you most likely wouldn’t find it if you didn’t know to go look for it. 

Starting with 7.1, you have capability to concurrently remove disk units in the system ASP, user ASPs, and on various independent ASPs. Prior to 7.1, you had to manual IPL to DST in order to remove disk units in the system ASP or a user ASP.  If you wanted to remove units from an independent ASP, the independent ASP had to be varied off.

Just think of the possibilities! If you want to upgrade your disk technology to the latest and greatest, you can now do it with only a single outage to migrate the load source unit for a single ASP system.  For user ASPs or independent ASPs, you can achieve a complete upgrade of all disk units with no outage at all. 

The capability is access via System Service Tools (SST).  You’ll notice a change on the Work with Disk Configuration panel, option 12, highlighted in the screen capture below.

After selecting option 12, you will see a new panel. As you can see from the options presented, not only can you start the remove process but you can pause the remove and resume one that’s paused. You can cancel the remove either with or without a balance.  You can also use either the option provided on the service tools panel or WRKDSKSTS to see the status of the remove operation.

Planning before beginning a remove of units will assure success with low business impact. Most important is to ensure enough free space on units that will remain to absorb the GBs from the disks you are removing. If the ASP threshold is exceeded while the remove process is running, the remove will be paused. 

Other items to consider while planning:

  • IBM i 7.1 is required.
  • Any server or blade hardware that supports IBM i 7.1 can be utilized.
  • If a remove is in progress when the system is powered down, ended abnormally, or an IASP is varied off, the remove will be paused. The remove must be restarted by choosing the resume option.
  • The load source unit cannot be removed from the system ASP.
  • Not all drives can be removed from an ASP. At least one must remain.
  • Moving drives between ASPs is not supported.The units must be removed from one ASP then added to the other ASP.
  • All units selected for removal must belong to a single ASP.
  • Only one ASP can be operated on at a time. Other ASPs removes may be paused but only one can be running.
  • No changes have been made to the remove processing that occurs during a manual IPL to DST.  A remove started at DST must complete before the IPL can continue.

Additional information about the remove process and other enhancements that increase your system’s availability can be found in the Knowledge Center.

I’d like to thank Sue Baker for writing this blog article. Sue is a Certified Consulting IT Specialist working for IBM’s Americas Advanced Technical Skills organization. Sue is currently focused on Power Systems hardware performance in the arenas of processor, memory, disk subsystems, and I/O. Sue consults with customers in the challenging arena of managing the operating environment to provide highly available, highly performing, and highly resilient Power Systems infrastructure.

This article was updated for currency on January 31, 2020.

This blog post was originally published on IBMSystemsMag.com and is reproduced here by permission of IBM Systems Media.