(This information applies only if you are upgrading from V5R2. The conversion does not affect the length of time for an upgrade.) As of V5R1, the "root" (/), QOpenSys, and user-defined file systems (UDFS) in the integrated file system support the *TYPE2 directory format.
The *TYPE2 directory format is an enhancement of the original *TYPE1 directory format. *TYPE2 directories have a different internal structure than *TYPE1 directories and provide improved performance and reliability. In releases V5R1 and V5R2, you could optionally convert to the *TYPE2 directory format using the appropriate conversion utility. Additionally, if the server was preloaded with V5R2, the directory format was *TYPE2.
If you have not previously converted to support *TYPE2 directories, the conversion to *TYPE2 directories automatically begins for any of the file systems shortly after V5R4 is installed. This conversion runs in the background during normal operations and should not significantly impact your system activity. For more information on integrated file system directory conversions, see Convert directories from *TYPE1 to *TYPE2 .