1 Topic by musicadi

  • musicadi
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Topic: Cannot shrink HFS+ partition

Hello everyone,

I have a 3TB HDD from my Apple Time Capsule, which had a failed power supply.

The HDD is now in an external case.

I've been having problems with HFS+, so I wanted to split the disk and use HFS+/EXT4 (or NTFS) combination.

On the HDD, there were 3 partitions (APConfig, APSwap and APData). The data is on APData (1,2 TB free space)

I tried to shrink this partition with Gparted 0.28.1-1 Live, but somehow that didn't work.

Then I decided to delete the APConfig and APSwap partitions (1GB in size each) and moved the APData partition to the beginning of the disk (apparently none of these steps were a good idea smile)

I am naturally getting file system errors in both Gparted Live and macOS, but the disk is being recognized, although I still can't resize it. Now I can't even move it anymore (I thought it would be wise to move it back to the right smile)

I created a 200MB EFI partition, but it's located at the end of the drive, so I guess it's kind of useless.

I know the cleanest way is to just backup the data and reformat the drive (I would need to borrow a 1,5/2TB drive for that), but I was wondering why I wasn't able to shrink the partition in the first place and if there is a way to move the big partition back to the end of the drive.

Thank you for your help!

2 Reply by class413

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Re: Cannot shrink HFS+ partition

In ms windows systems' regular partition schema, the EFI system partition (ESP) is the first partition on the drive (although this is not mandatory by the EFI specification), and after that there is the Microsoft Reserved Partition (MSR). I'm not aware of Apple requirements on this point. Anyway, in a GPT scheme the last MiB of the drive is used by the system for a backup copy of the partition table. The Apple partitioning scheme is even more complicated, keeping compatibility with both GPT and MBR.

In order to know more on what happened about (non-) shrinking the partition, it would be very helpful to see the "GParted details". You can save it just after the GParted message on success or failure.

Backup your data is the best idea, not just to modify partitioning or re-install the O.S. There is no warranty that any hard drive will work flawlessly forever. Failures can occur at any moment. Repeated partition move operations could increase hardware failure risk, as they cause mechanical stress of the drive moving parts, much more that during the normal disk operation.

*** It is highly recommended to backup any important files before doing resize/move operations. ***

3 Reply by musicadi

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Re: Cannot shrink HFS+ partition

Hi,

Thank you for your reply.

Already saved the Gparted details (although it's on the Live USB, which OS X cannot read smile).

The error showed was "Filesystem error"

4 Reply by gedakc

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Re: Cannot shrink HFS+ partition

In order to reduce the chance of data loss, GParted disabled partition and file system resize/moves when any errors are detected in the file system.

If the file system errors cannot be corrected, then GParted will not be able to resize the partition and the file system within.

It might be a good idea to check if the disk is failing by looking at the smart monitoring statistics for the drive.  This can be done with the GParted Live image and the included GSMartControl application.

5 Reply by musicadi

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Re: Cannot shrink HFS+ partition

gedakc wrote:

In order to reduce the chance of data loss, GParted disabled partition and file system resize/moves when any errors are detected in the file system.

If the file system errors cannot be corrected, then GParted will not be able to resize the partition and the file system within.

It might be a good idea to check if the disk is failing by looking at the smart monitoring statistics for the drive.  This can be done with the GParted Live image and the included GSMartControl application.

I see, thank you for your answer! Will check that as soon as I get a chance and post the results.

6 Reply by musicadi

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Re: Cannot shrink HFS+ partition

gedakc wrote:

In order to reduce the chance of data loss, GParted disabled partition and file system resize/moves when any errors are detected in the file system.

If the file system errors cannot be corrected, then GParted will not be able to resize the partition and the file system within.

It might be a good idea to check if the disk is failing by looking at the smart monitoring statistics for the drive.  This can be done with the GParted Live image and the included GSMartControl application.

Hello,

I managed to run the GSmartControl application and there are no errors shown.

So, here's what I did so far

1. Deleted all partitions except the main HFS+ partition
2. Moved the main partition to the left (yeah, I know, bad idea)
3. Moved main partition back to the right, leaving 200mb space before

For some reason though, Gparted left 201mb free space before.

Anyway, I used gpt on my mac to recreate the EFI partition and cloned a functioning EFI partition to it.

Now I'm having the problem that the HFS+ partition has index 1, while the EFI partition has index 2 smile

Now, when tryi  to resize the HFS+ partition, Gparted crashed with the error "Segmentation fault"

7 Reply by gedakc

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Re: Cannot shrink HFS+ partition

Do you have a backup of your data?  If not then I highly recommend you make a backup.

If you already have a backup of your data, then it might be quicker to reinstall Mac OS X and then restore your data.

As for the segmentation fault, we need more information.  Can you capture the core dump (be sure to use "ulimit -c unlimited befehand), and then provide a stack dump back trace?