What is the disk PCI-Express Internal Physical Volume

lomontman

macrumors newbie
Original poster
Nov 9, 2018
10
0
My wife and I have identical iMacs with the same SSD drives. On her computer a drive "PCI-Express Internal Physical Volume" shows up - it does not appear on my iMac at all. It cannot be unmounted. What is it and how do I make it disappear?
 

SecuritySteve

macrumors 6502a
Jul 6, 2017
833
971
California
It sounds to me like perhaps your drives were partitioned or formatted differently. Can you take a screenshot of your disk utility with all devices shown? It should look something like this, after you select the "View" option in the left to show all devices:

Screen Shot 2018-11-09 at 8.13.15 AM.png


Edit: We probably should see the output of both iMacs.
 

SecuritySteve

macrumors 6502a
Jul 6, 2017
833
971
California
It looks like there are either two physical drives in one of the computers, or there was some partitioning issue that caused the Macintosh HD to be installed on different partitions. I find it odd that if your iMacs are identical, one of your Macs has 500 GB of storage while the other has 1 TB. Are you sure that you don't have a Fusion drive in one of them, and a full SSD in the other?

You may want to look into the System Information (In utilities) -> PCI or NVMExpress and making sure the hardware listed matches under those two windows.
 

lomontman

macrumors newbie
Original poster
Nov 9, 2018
10
0
Both drives are full SSD. I did indeed forget that they are different capacities. Her iMac was upgraded from one that did have a Fusion drive. So perhaps the transfer process had to proceed this way but I would think the Migration process would be sophisticated enough to not propagate the old drive structure onto the new one.
[doublepost=1541787919][/doublepost]Here are some more screen shots of the drives:

Screen Shot 2018-11-09 at 1.18.39 PM.png
Screen Shot 2018-11-09 at 1.22.11 PM.png
Screen Shot 2018-11-09 at 1.22.46 PM.png
Screen Shot 2018-11-09 at 1.22.52 PM.png
 

SecuritySteve

macrumors 6502a
Jul 6, 2017
833
971
California
Yeah there must have been a formatting issue. My bet is the old Fusion drive had 28 GB of space, and when it was migrated a 28 GB partition was created to house that drive's data.

All depends on how you migrated it. There are so many ways to do it, all of which have slightly different results. You might be able to get rid of the partition by reclaiming the space onto the parent drive. It's been a while since I've handled that, but I seem to recall that if you boot the Mac in recovery mode to access Disk Utility at the boot level, it can merge disks.
 

lomontman

macrumors newbie
Original poster
Nov 9, 2018
10
0
That makes sense. I'll do a little research to see if I can merge the drives. Thanks for your help. I do remember I had some trouble with the migration, though I can't remember exactly what the nature of the problem was. So perhaps the weird drive structure is based on that issue.
It's not that big of a deal - it doesn't affect the performance of the computer - just one of those little things that I'd like to clean up.
 

mikehalloran

macrumors 68000
Oct 14, 2018
1,712
435
The Sillie Con Valley
Yeah there must have been a formatting issue. My bet is the old Fusion drive had 28 GB of space, and when it was migrated a 28 GB partition was created to house that drive's data.

All depends on how you migrated it. There are so many ways to do it, all of which have slightly different results. You might be able to get rid of the partition by reclaiming the space onto the parent drive. It's been a while since I've handled that, but I seem to recall that if you boot the Mac in recovery mode to access Disk Utility at the boot level, it can merge disks.
Formatting an APFS drive and creating an HFS+ partition in the process is what happened. I've seen this before—heck, I caused it during testing. That was the easy part.

Consolidate the space on an APFS drive while eliminating the HFS+ partition and retaining all my data... I recall that it took a long time. First, I referenced three "expert" web sites with conflicting instructions and had all three up on my side monitors. It took both Terminal and Disk Utility working together to accomplish it. When it finally worked, I could not recall the exact steps that made it happen.

My other choice was always to wipe the SSD and do a complete Time Machine Restore. Although prepared to do that if I had to, I was spared.

One of my tasks when I replace this 2010 (soon?) is to replicate the above and see if there is a clear set of instructions that works to consolidate the space. If not, I'll write a set of my own.

Since your HFS+ partition is so small, you might want to leave it alone. I wish I could point to a web site and say, This is exactly how you do it. Perhaps someone else can.
 

lomontman

macrumors newbie
Original poster
Nov 9, 2018
10
0
My gut thought was that merging the drives is not going to be simple - I'm not that knowledgable about the intricacies of computers - most of my solutions to problems do come from knowledge posted on the web and if there are multiple experts that disagree about how to solve the problem then I probably won't be able to work it out. I did indeed have the thought that I'd just wipe the drive and restore from a TM backup - the challenge there will be finding enough time when my wife is not using the computer to actually do it. So the current drive status may stay put for a while. Thanks for your suggestion.
 
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