disk utility: problem with resizing a partition

Nope... looks like you can't do this with the diskutil command line either:

Resizing encountered error on disk disk1s1 Data: Could not modify partition map (-9986)

This was with an MBR. I'm trying this on an external drive where I need both a FAT partition for Windows and a JHFS+ partition for OS X. My questions are:

1. Does anyone know if windows is able to read a FAT partition stored using GUID so that I can use these resizing features in Disk Utility but still have a usable volume in Windows?

2. People mentioned that you'd need a 3rd part tool for resizing. Can anyone name some 3rd party tools that will work with MBR and HFS+?

3. Is there a way to non-destructively convert from MBR / APM / GUID (even with a 3rd party tool)?

Thanks!

One interesting thing that I noticed is that when I go to the partition tab of my external drive in Disk Utility, it seems to think that +the drive is empty+, showing "Available space" to be 231.8 GB for a 232.8 GB partition. That seems a little odd…

You can split a partition, or merge two partitions that happen to be consecutive, and I think that's about it. *You can't make one partition larger at the expense of making another smaller.*

But can I make one partition smaller and free up space for the second partition to be larger? P-1 is 30GB and it only needs to be 10GB. P-2 is the remaining 400+GB of the drive. Both partitions are Mac Extended (Journaled) on a FireWire drive connected to G5 running Leopard.

I'd like to do this on the fly if it can be done safely.

Disk Utility "Partition" window reads:

"To resize the volumes on the selected disk, drag the dividers between them and click Apply.

"This volume will not be erased. Size 29.9 GB...."

I have the first partition selected.

If I drag the dividers as indicated to make the first partition even smaller (provided, of course, that I still leave enough room for the existing data) will the second partition also get bigger and will the data on both partitions remain intact? Has anyone actually done this?

Ken

I don't think that will work. The second partition won't get bigger. From Help "Enlarging a Volume"

To enlarge a volume, you must delete the volume that comes after it on the disk, and then move the volume’s end point into the freed space. You can’t enlarge the last volume on a disk.

One way to think of it is you can't change a partition's "start" point, but you are now able to adjust its "end" point (size).

So you pretty much have to re-do the second partition in your case, erasing the data. 😟

Message was edited by: Barbasol

Hello,

From my own experience with Leopard the repartitioning on the fly, enlarging a volume and undoing a partition work perfectly fine. I am working with a PPC so I cannot speak for GUID, though I see no reason for it not to work with GUID either. Most problems are experienced by simply not being generous enough in the sizing of the main partition you are creating from. Just because a partition is only using a portion of its space to hold your data, there is also a lot of space being used to store data which you cannot see. It will remain there until it is written over. (That is why you have the option in Disk Utility to "erase empty space.") Make your main partition bigger than you have been allowing. It needs more space than you realise. Also be aware that if you require space for burning DVD's etc, even temporary files require space for storage before they delete themselves. Eg: Toast Converted Items. If you come up with the error, "Not enough space" you need to make your first partition bigger. To delete a volume is as simple as selecting it in the partition window, and hitting the - button underneath. Then apply. This will restore the space right back to the original volume again. Hope this helps some.

Regards,
Ben.

Hi drdocument,

The simple answer is NO. You cannot make your main partition smaller. If anything you need to make it bigger. Give your second (or third depending how many you are creating) partition LESS space. While you are creating a new partition, you have now made it apparent to the main partition that it is going to need more space to hold temp folders and files should you desire to burn DVD's etc and require the temp storage space. You see, now that you have robbed it of its free space, it has to allow space of its own to function in the every day routines of computing. I have successfully created a partition on a 120GB (111Gb formatted) holding 60Gb of data already. I kept stretching it out until it allowed me to create.
It gave the option to create a 34 Gb extra partition. That would suggest that the partition holding my 60Gb of data required at least an extra 10 to 20Gb if it was to be divided. You may gain some more space by using the "erase empty space" option in Disk Utility before you partition. The clue is to be generous with your Primary partition. It needs space. More than you realize.

Thanks.

To clarify, it was not my "primary" partition that I wanted to make smaller, but a minimum system on external drive from which I could occasionally restart solely to run a couple disk utilities like Disk Warrior, which runs much faster if the computer is booted from a hard drive than it does when booted from a CD. In my situation, on this external drive, I wanted to make Partition 1 (the "utility startup system") smaller (from 30GB down to 10GB), to free up more space for Partition 2 to use as Time Machine destination.

I was in fact able to reduce the size of P-1, but couldn't really do anything with that freed-up 20GB because I couldn't move the "start point" of P-2 to "add it" to the TM destination partition. The really helpful thing that I learned in this thread is that with Disk Utility we can move the end point of a partition but not the start point.

I wholeheartedly agree with you about needing a good amount of free space on the primary drive or partition. I always try to keep at least 25 percent free on my 80GB internal startup drive, and dedicate a little bit of time each week to creating more free space by archiving and deleting files no longer needed.

bensbits,

I wish I could duplicate your results but so far I cannot. This is on an external Firewire-connected drive, partitioned in APM scheme, with 4 partitions, all HFS+ (Journaled). I have partitions (in order) of about 98 GB, 66 GB, 20 GB, & 5 GB. (The drive is nominally a 200 GB one, about 189 GB formatted.)

What I would like to do is combine the last two partitions so it is 98/66/25. I have no problem deleting the 5 GB partition with the "-" button, but I cannot find a way to 'grow' the 20 GB one into its space. I followed the instructions in the Disk Utility Help topic *Enlarging a volume*, and at step 3 tried both dragging the divider at the bottom of the volume in the Volume Scheme list & selecting the volume, and entering a value in the Size field. In both cases, I get the "Filesystem resize support required, such as HFS with Journaling enabled" error.

In fact, all I can do is click the "+" button, which does add back the unused 5 GB space as a new partition, but even that doesn't work right: as George Orthwein reported, Disk Utility hangs on "Modifying partition map" step indefinitely -- I've let it run for up to 3 hours & it still doesn't finish. When I quit Disk Utility & get the warning about the disk possibly being unusable, what happens is the partition is recognized only by its UNIX name ("disk s1/14" or something like that), & D.U.'s repair fails with the not to helpful message that it failed, but if I go to the "Erase" tab & do a regular (non-zeroing) erase of the partition, it is restored to usability.

Note that neither of these partitions has an OS installed on it (so temp file space is not an issue), & only about 8 GB of the 20 GB partition has any data. I should at least be able to split this partition with the "+" button, & doing so with the 5 GB section after it free does show the expected total space divided equally into two partitions before the "Apply" button is clicked, but no matter what, I get the same failure with the error about needing resize support.

Hi RC,

I see what you're trying to do. Just follow these steps.
1. Open Disk Utility.
2. Click on the device you want to partition or resize in the Left panel, and then select the Partition tab on the right. If I understand you correctly you want to bring the final partition of 5Gb back into the 20Gb thus creating one 25Gb partition.
3. Highlight the final partition (5Gb) and hit the - button. You will be prompted to remove the volume. Click "Remove". This will eliminate your 5Gb Partition altogether.
4. If you look closely at the partitions on the bottom right hand corner, you will see the typical Macintosh "Drag thumb print". On your 20Gb Partition simply drag the window to the full extent of the Partition window (Right to the bottom) This will allow your 20Gb to use the remaining 5Gb. Hit apply. Wulla... Youre done. Back to two partitions. Hope this helped.

Regards,
Ben.

Hi RC,

Sorry I neglected to inform you that before you can drag and resize the partition inside the window, you must first select it. Once selected it should be highlighted with a blue aura. You can then drag and resize it. As you drag the window, you will notice the "size" window following suit. For "your" purpose, drag it right to the bottom.

Regards,
Ben.

Ben:

I have followed the steps you listed many times now. Everything is fine at step 3 -- the 5 GB partition is deleted with no problem or error. Step 4 (including the variations using the size text box, the corner tab you mention, & simply dragging the bottom border of the 20 GB partition downward) does indeed show what I want, but when I click the Apply button & confirm that I want to resize the partition, within a second or so I get the error message "Filesystem resize support required, such as HFS+ with Journaling enabled."

FWIW, I have also tried splitting the 5 GB partition by selecting it & then clicking the "+" button. According to Disk Utility's help topic *Creating new volumes on a disk*:

+Disk Utility splits the volume into two, leaving the data in one of the new volumes. If the volume is less than half-full, Disk Utility creates two volumes of equal size. Otherwise. it creates one volume large enough for the data, and another volume with the remaining space.+

This also results in the 'resize support required' error when I click Apply. Additionally, I cannot choose how to format the volumes that will be erased or created as described in step 4 of that help topic -- the only format choice is Mac OS Extended (Journaled) & if I select it, the name of the second split volume remains "EMPTY NAME" no matter what I put in the name field.

As I said, this drive is an external Firewire one using the APM scheme, & all the partitions are HFS+ with Journaling enabled. It is connected to my G5 iMac & contains (in the second listed partition of about 66 GB) the Leopard OS install I normally boot from. However, just in case this was tan issue, I have also tried resizing the 20 GB partition while booted from the Leopard DVD, using its copy of Disk Utility, so I do not believe that is the problem.

What might be the problem is this drive does have an OS 9 boot partition on it -- others seem to be reporting the same failure message on drives partitioned this way, whether internal or external. It would help a lot to know if you (or others who have successfully resized APM disks) have done so on any drives that have this OS 9 boot partition.

Thanks in advance for looking into this.

Hi RC,

I unchecked the OS 9 Drivers option before formatting my Hard Disk. Leopard doesn't support OS 9 and neither does the GUID format, so unless you want the external to be mounted on an OS 9 machine there is no point. You cannot have only one partition with OS 9 Drivers. You must format the entire disk with those drivers if you are to have OS 9 Capability. Its part of the initial formatting process, not the partition set up (Unless you are partitioning from scratch). I only received the "empy space" issue when I didnt size the primary partition large enough to cope with the split. Try making your primary partition larger before attempting to add more partitions. It wont let you do it if you havent given it enough room to cope with new partitions. Start from scratch again with Your primary partition (unless you have already added data) and give it more space before trying to create extra. I'll check back again later. Gotta go to work.

Regards,
Ben.

Ben,

Thanks for the comments. I do understand that Leopard doesn't support OS 9, but I have several Macs that do, & will continue to use the APM scheme on my external drives because it is capable of booting both PPC & Intel Macs.

Regarding your other comments, I'm not sure what you mean: OS 9 driver partitions are very small partitions clustered at the beginning of the drive, just after the APM partition itself, & one is loaded into memory as part of the OS 9 boot process. They are not scattered over the entire drive; in fact, the reason the disk needs to be reformatted to install them is because there is no room reserved for them at the beginning of the drive otherwise. (Back in the days of System 7, various third party formatting tools allowed one to leave free space in this zone to make it possible to update the drivers with larger ones without reformatting & do other interesting things, but with the introduction of "New World" Macs, they largely faded away into obscurity.)

Also, I'm not talking about an "empty space" issue but an "EMPTY NAME" entry (I'm not shouting; it appears that way) in Disk Utility's restore tab's graphic representation of the partition map. Please reread that part of my post more carefully for more details.

Regarding splitting a partition, I'm not sure how you managed to move the resize line into the used space of any partition -- one feature of the new live resize capability is that it should not let you do that & indeed this is how it works for me. In any event, I don't know what you mean by "primary partition" -- I have two large partitions, one each for Tiger & Leopard, & each is less than 1/2 full. The two smaller partitions have no OS on them & no user files -- they are both empty except for the overhead of the filesystem itself. It is these partitions I want to combine -- the two partitions with content are untouched.

Hi RC,

Sorry about the misunderstanding on the OS 9 Drivers. I do understand that the drivers are not scattered all over the drive. A few people think however that they can have one partition "with" OS 9 Drivers and another "without" on the same disk. I was speaking to you thinking you might be one of them. I also totally agree with you on the APM scheme as it is definitely possible to have a triple boot drive for OS 9, Intel & Apple on the one disk if you know what youre doing.

By "primary" partition, I mean the partition being used to create others from. In your case this would be the First partition, the largest one (98Gb) I now realise that your first two partitions 98Gb &66Gb both hold data, approximately 50% and your 20Gb and 5Gb are both without data. Correct...? (Half the battle on these threads is trying to understand each other.) I realize also that you had no problem creating partitions, but you are in need of REsizing.

The only way I was able to emulate the "empty name" (Im sorry, I did mean to say empty name and not empty space in my previous post) problem was when I chose to erase the partition before trying to remove it. I closed DU and then opened it again and went through the same procedure, this time withOUT trying to erase it first. Dont worry about erasing. Lets start from scratch.

Are you able to remove the last partition....? (Click the - button and remove it) If so, once you have removed it, are you able to highlight the 3rd partition..? (Is it highlighted with a blue aura when you click on it..? The next step if you have gotten this far is to look carefully at the bottom right hand corner for the drag point (click and drag thumb print just like on any finder window or safari for stretching or resizing the window) I have these on the highlighted partitions which enables be to drag them to size. What you need to be able to do is drag your third partition to the full extent of the window. (Down obviously) and then apply. This "should" merge your 20Gb and 5Gb into one. I know, I know.... Should...! One more question... Did you partition your hard disk originally with Leopard DU or a third party Partition software...? Just a thought..! All of my partitioning was done within Leopard DU. Maybe you cannot undo what was done with 3rd Party Software.... Hang in there, there must be a solution.

By the way, what happens if you remove both your 5Gb AND 20Gb and drag the 66Gb to the bottom..?
The file system resize error is not one I have seen...

Regards,
Ben.

Message was edited by: bensbits