Q: How to merge two partition?

Those partitions are on separate drives and can't be merged without creating a RAID array, which isn't possible in all configurations.

(108626)

The fact that they're listed under /dev/disk0 and /dev/disk1 means that they're on separate drives. All the partitions on a single drive will fall under the same /dev item.

If you're referring to the two partitions on disk0, yes. Note that the Disk Utility can't change the starting point of an existing partition.

(108628)

I know of no application that can do that. At least, I've never heard of such an app.

You have core storage which is merging two physical disks like a 'Fusion drive'.

diskutil cs list

Will give you more info.

Unable to reformat/repartition Fusion Drive

I think you will need to delete or convert the cs container, however I have not done this & I would backup all the data on both disks & then look out how to reformat them and then restore the data.

You can do it, but needs to be a semi manual process.

1) Copy everything on the second partition to another physical drive, such as an external hard drive. To be safe, you may want to clone the contents of both partitions to an external drive, also to separate partitions. That way, once you get to the step where you remove the second partition on your main internal drive, you for sure have it backed up. Also in case of a tragic screwup, you can boot to the external and clone things back. Make sure the external drive is bootable by having it partitioned with a GUID partition table. Any or all partitions being Mac OS Extended does not automatically mean you can startup to it if the partition table is not GUID.

Example:

Let's just presume "Snow" is the partition I want to remove and have "Mavericks" take over its space. I would clone all content on drive "Snow" (which will be the drive icon's same name on your desktop) to the external drive. Once the backup is complete, move to the next step.

2) Launch Disk Utility. Highlight the internal drive's physical drive icon, which is indented to the left. Click on the Partition tab (as I did above). Here I would click on the "Snow" partition at the right (in the graphical display, not the left hand list) and click the minus button below it to remove that partition. The space will be displayed as an empty gray area.

3) You can now grab the lower right corner of your remaining partition down to fill the space and have it take over the entire drive. Click Apply.

In the example above, I would drag the corner of "Mavericks" down to fill to the bottom, leaving two partitions. If wanted to, I could remove both "Mavericks" and "Snow" and then drag "Video" down to take over the entire drive.

4) Copy everything back from the external drive you backed up from the now removed partition.

Kurt Lang wrote:

 

You can do it, but needs to be a semi manual process.

 

…

Are you sure about this?

Haring01 has 2 physical disks where you are demoing merging partitions on one disk. It looks like a logical volume group is spanning the two disks for Haring01's setup.

Oh, crud! Yes, Drew, you are quite correct. Don't know how I missed that as it's been mentioned more than once.

Then we're back to no, it can't be done without setting it up as a RAID. And as Niel noted, that can't always be done, either.

Judging by your screenshot, maybe. You have cropped out the part that includes the 'Disk description'. I expect any info about core storage or volume groups will appear that section.

The sidebar can also help to see what we are looking at…

NOTE: Your screenshot has tabs for 'First Aid' & 'Partition' ONLY

Kurt's has 'First Aid', 'Erase' 'Partition' and 'R(ecovery)'. I also see Kurt's tabs when selecting A DISK in Disk Utility, you have selected something different.

We are looking at different things & you are giving us 1/2 the picture.

cmd+shift+4, tap space bar click the Disk Utility window. Post the screenshot here

I've never encrypted a drive, so I have to presume that's why even the left indented drive is also named "Manuel" instead of the drive's make, size and model number.

Please turn off FileVault and restart. I don't know how long it takes to decrypt a drive, so don't know if you'd want to do that. But from what I can see from your screen grabs, you're going to have to before you can proceed. I say that because the partitions don't show the dashed lower right corner on either one, which must be a limitation of being encrypted?

Might want to wait until someone who has experience using FileVault confirms or corrects my statements.

You can't merge the bottom partition with the top, but you can merge the top with the bottom. So if you need to keep the contents of the second partition, you must delete the contents of the first partition and move the contents of the second to the first. You can do that with cloning software or just use the restore feature of disk utility to restore the contents of the second partition to the first. Once done, use disk utility to delete the second partition to create one Single volume.

You may need to format the first partition the same as the second: MacOS Extended Journaled.

See how the second screenshot lists 'Encrypted Logical Partition' in the bottom left.

That is not a single disk - it is representing a pool of disks grouped in a similar fashion to RAID (in general terms). These are listed as 2 disks as your first post shows (two items under /dev). Select the first 'Manuel' in the left hand list & it may show you information about the 'logical partition'.

We are back to square 1, as Neil said earlier…

Those partitions are on separate drives and can't be merged without creating a RAID array, which isn't possible in all configurations.

I don't know the correct way to split these disks or the best way to merge them, sorry, you'll need to look into core storage or nuke both disks & reformat them as far as I can tell.