How To
Summary
Starting at 7.2 (V7R2) with Technology Refresh 2 (TR2) or 7.3 (V7R3) with any Technology Refresh, IBM i may allow migrating the Load Source (LS) disk unit to a smaller size by using the following procedure to move data off of the LS and check the minimum size.
Note: Earlier releases of IBM i (V7R1 and older) only supported migrating the LS to the same size or larger unit.
Note: Base 7.4 (V7R4) and higher supports migrating to smaller units using the copy disk unit data function in DST. It will first move off an amount of data equal to the difference in drive sizes, then readjust the High Water Mark, and finally copy the remaining data to the smaller unit. This document is not needed at V7R4 or higher.
Steps
- Check the current minimum size the LS can be copied to
- Run STRSST command from IBM i command line
- Log into System Service Tools with Service Tools user ID and password
- Option 1 - Start a service tool
- Option 4 - Display/Alter/Dump
- Option 1 - Display/Alter storage
- Option 2 - Licensed Internal Code (LIC) data
- Option 14 - Advanced analysis
- On the top line type option 1 and command DUMPFSMAPINFO then press enter
- On the options line type -D and press enter
- Look for first line that says "High Water Mark:" and write down the hex number on that same line
- Convert the hex number to decimal (example: 29B0000 = 43712512)
- Multiply by 4096 to get the size in bytes (example: 43712512 x 4096 = 179046449152)
- Divide by 1000000 to get the size in millions of bytes (M) (example: 179046449152 / 1000000 = 179046.4)
- Round value up to whole integer (example: 179046.4 => 179047)
- Check the size of the non-configured unit that is intended to replace the LS (WRKDSKSTS or check in SST)
- If the non-configured unit equals, or is larger than, the value from step 1, you can migrate to the new unit
- If the non-configured unit is less than the value from step 1, continue with step 5
- Reduce the storage allocated on the LS and rebuild the free space map
- Mark the LS for no new allocations with command STRASPBAL TYPE(*ENDALC) UNIT(1)
- Start draining data off the LS using command STRASPBAL TYPE(*MOVDTA) TIMLMT(*NOMAX)
- Monitor status using command CHKASPBAL until the balance function is complete
- Set the system to compress job tables on next IPL using command CHGIPLA CPRJOBTBL(*NEXT)
- Perform a normal IPL (note: job table compression can take a significant amount of time)
- Start another drain using command STRASPBAL TYPE(*MOVDTA) TIMLMT(*NOMAX)
- Monitor status using command CHKASPBAL until the balance function is complete
- Perform a second normal IPL to rebuild the free space map for unit 1
- Resume allocations for unit 1 using command STRASPBAL TYPE(*RSMALC) UNIT(1)
- Repeat step 1 to determine the new minimum size that can be used to replace the LS
- If the non-configured unit equals , or is larger than the new value from step 6, then you can migrate to the new unit
- If the non-configured unit is less than the value from step 6, you will need a larger drive to do the migration
Additional Information
Document Location
Worldwide
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Document Information
Modified date:
26 September 2023
UID
ibm10886761