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Authored by: lstewart on Nov 19, '02 03:35:01PM
Someone please correct me if I'm wrong, but I don't think it's possible to resize partitions without losing the information on them.

I came up with a procedure similar to the above back when I was juggling partitions between OS 9, Mac OS X Server 1.x, and LinuxPPC. There is a port of pdisk that works under OS 9, and I used it with great success, without even booting off the CD-ROM. (It would modify the tables of the booted partition, but the changes would only become active when you rebooted.)

pdisk works great for wiping & redefining partitions, but it's not cut out to resize or move existing partitions without data loss. That's one of the things I miss from my past life on the PC... PowerQuest's Partition Magic. That thing would resize, move, consolidate, slice, dice partitions on a PC like nothing else. Too bad they're not in the Mac market. (I actually know an engineer there, and tried to talk him into a Mac port, but I was starting on the wrong end of the management chain. ;-)

Once I foolishly tried to "consolidate" two contiguous HFS+ partitions (using pdisk - delete the second partition and resize the first one to take up all the space) while retaining the data on the first one. It really hosed things. I had to run every disk utility I could get my hands on several times each before the partition would mount, and if my memory serves, it never worked completely (without errors) again until I reformatted it.

I've looked at several HFS+ disk utilities, and though I found one that claimed to do partition resizing for (legacy) HFS disks without data loss, nothing I found would work for HFS+. It's been a couple years since I researched it, though, so maybe there are more options now.

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Authored by: gvitale on Nov 21, '02 07:36:50AM

as pointed out by dolfs, pdisk is not destructive, as it does not manipulates the partitions themselves. In other words it relocates disk blocks to logical partitions, without actually writing data to the blocks themselves. This means that you can split an existing partition (lets say 40% full) in two (or more) partitions and still preserve the content of the original disk/logical partition. The first of the newly created partitions must have enough blocks allocated ti it in order to accommodate all the data of the original partition (that is at least 40% of the blocks have to be relocated to the first of the newly created partitions), and all the data have to be moved to that blocks PRIOR repartitioning the original disk/logical partition (this can be done with Norton SpeedDisk, selecting CD master as optimization profile). After repartitioning, all the data (and the directory information) will still be present in the first new partitions, and you should run a disk repair utility to fix inconsistencies in the disk catalogue map.
You can practice this with a disk image, before doing thinks to your HD ;-).

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iPartition will do this
Authored by: Coriolis Systems on Jul 05, '04 12:55:23AM

Our product, iPartition, will let you resize partitions easily without having to reformat. See our site for more information.

We should also say that we definitely do not recommend the method espoused by some people in this thread whereby pdisk is used to change the size of the partition and then a disk repair tool is used to clear-up the resulting mess. Even with a disk repair utility involved, the volume that results from this operation is most likely quite broken, as the volume data structures will not have been resized correctly to take account of the new size of the volume.

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