pvmove(8) - NetBSD Manual Pages

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PVMOVE(8)                                                            PVMOVE(8)




NAME

       pvmove - move physical extents


SYNOPSIS

       pvmove    [--abort]    [--alloc   AllocationPolicy]   [-b|--background]
       [-d|--debug]   [-h|--help]   [-i|--interval   Seconds]   [-v|--verbose]
       [-n|--name  LogicalVolume] [SourcePhysicalVolume[:PE[-PE]...] [Destina-
       tionPhysicalVolume[:PE[-PE]...]...]]


DESCRIPTION

       pvmove allows you to move the allocated physical extents (PEs) on Sour-
       cePhysicalVolume  to one or more other physical volumes (PVs).  You can
       optionally specify a source LogicalVolume in which  case  only  extents
       used  by that LV will be moved to free (or specified) extents on Desti-
       nationPhysicalVolume(s).  If no DestinationPhysicalVolume is specified,
       the normal allocation rules for the volume group are used.

       If  pvmove  gets  interrupted for any reason (e.g. the machine crashes)
       then run pvmove again without any PhysicalVolume arguments  to  restart
       any  moves  that  were  in progress from the last checkpoint.  Alterna-
       tively use pvmove --abort at any time to abort them at the last  check-
       point.

       You  can run more than one pvmove at once provided they are moving data
       off different SourcePhysicalVolumes, but additional pvmoves will ignore
       any  logical  volumes  already in the process of being changed, so some
       data might not get moved.

       pvmove works as follows:

       1. A temporary 'pvmove' logical volume is created to store  details  of
       all the data movements required.

       2.  Every logical volume in the volume group is searched for contiguous
       data that need moving according to the  command  line  arguments.   For
       each  piece  of  data  found,  a new segment is added to the end of the
       pvmove LV.  This segment takes the form of a temporary mirror  to  copy
       the data from the original location to a newly-allocated location.  The
       original LV is updated to use the new temporary mirror segment  in  the
       pvmove LV instead of accessing the data directly.

       3. The volume group metadata is updated on disk.

       4.  The  first  segment  of  the pvmove logical volume is activated and
       starts to mirror the first part of the data.  Only one segment is  mir-
       rored at once as this is usually more efficient.

       5.  A daemon repeatedly checks progress at the specified time interval.
       When it detects that the first temporary mirror is in-sync,  it  breaks
       that  mirror  so that only the new location for that data gets used and
       writes a checkpoint into the volume group metadata on  disk.   Then  it
       activates the mirror for the next segment of the pvmove LV.

       6.  When  there are no more segments left to be mirrored, the temporary
       logical volume is removed and the volume group metadata is  updated  so
       that the logical volumes reflect the new data locations.

       Note that this new process cannot support the original LVM1 type of on-
       disk metadata.  Metadata can be converted using vgconvert(8).



OPTIONS

       --abort
              Abort any moves in progress.

       -b, --background
              Run the daemon in the background.

       -i, --interval Seconds
              Report progress as a percentage at regular intervals.

       -n, --name  LogicalVolume
              Move only the extents belonging to  LogicalVolume  from  Source-
              PhysicalVolume  instead of all allocated extents to the destina-
              tion physical volume(s).



EXAMPLES

       To move all logical extents of any logical volumes on /dev/hda4 to free
       physical  extents elsewhere in the volume group, giving verbose runtime
       information, use:

            pvmove -v /dev/hda4



SEE ALSO

       lvm(8), vgconvert(8)



Sistina Software UK    LVM TOOLS 2.02.44-cvs (02-17-09)              PVMOVE(8)