394Administering hot-relocation

Moving and unrelocating subdisks

Examining which subdisks were hot-relocated from a disk

If a subdisk was hot relocated more than once due to multiple disk failures, it can still be unrelocated back to its original location. For instance, if mydg01 failed and a subdisk named mydg01-01was moved to mydg02, and then mydg02 experienced disk failure, all of the subdisks residing on it, including the one which was hot-relocated to it, will be moved again. When mydg02 was replaced, a vxunreloc operation for mydg02 will do nothing to the hot-relocated subdisk mydg01-01. However, a replacement of mydg01 followed by a vxunreloc operation, moves mydg01-01back to mydg01 if vxunreloc is run immediately after the replacement.

After the disk that experienced the failure is fixed or replaced, vxunreloc can be used to move all the hot-relocated subdisks back to the disk. When a subdisk is hot-relocated, its original disk-media name and the offset into the disk are saved in the configuration database. When a subdisk is moved back to the original disk or to a new disk using vxunreloc, the information is erased. The original disk-media name and the original offset are saved in the subdisk records. To print all of the subdisks that were hot-relocated from mydg01 in the mydg disk group, use the following command:

#vxprint -g mydg -se 'sd_orig_dmname="mydg01"'Restarting vxunreloc after errorsvxunreloc moves subdisks in three phases:

■vxunreloc creates as many subdisks on the specified destination disk as there are subdisks to be unrelocated. The string UNRELOC is placed in the comment field of each subdisk record.

Creating the subdisk is an all-or-nothingoperation. If vxunreloc cannot create all the subdisks successfully, none are created, and vxunreloc exits.

■vxunreloc moves the data from each subdisk to the corresponding newly created subdisk on the destination disk.

■When all subdisk data moves have been completed successfully, vxunreloc sets the comment field to the null string for each subdisk on the destination disk whose comment field is currently set to UNRELOC.

The comment fields of all the subdisks on the destination disk remain marked as UNRELOC until phase 3 completes. If its execution is interrupted, vxunreloc can subsequently re-use subdisks that it created on the destination disk during a previous execution, but it does not use any data that was moved to the destination disk.

If a subdisk data move fails, vxunreloc displays an error message and exits. Determine the problem that caused the move to fail, and fix it before re-executing vxunreloc.