Kernel Panics When Running macOS off External SSD

[_.adamjames._]

Hi all,

Having a bit of iMac trouble here...

So, I was extremely fed up of the woefully slow speeds from the HDD on my Late 2012 iMac. I decided that I didn’t feel like tearing it apart in order to swap out the hard drive for an SSD. After looking around on various other forums I saw that quite a lot of people have had success booting off an SSD in an external drive enclosure. So I went and did just this. I’m using a Samsung 850 Evo in an external enclosure over USB 3.0 (as both my thunderbolt ports are driving extended displays), and for a while everything ran perfectly and it made a huge difference - almost felt as snappy as my Late ‘16 MBP. Anyway as of today, it keeps freezing randomly, then followed by a restart and a kernel panic report.

Anyone got any ideas what cause be causing this? I’ve seen on one forum post that the issue can be to do with drive enclosures that are powered over USB rather than with an external power supply - but I’m not too sure about that as it has worked for several weeks until now?

Thank you in advance and hope you are all well,

AJ

 

[nambuccaheadsau]

Go into Console and post the log. Any new software or extensions lately?

 

[_.adamjames._]

Hi there,

Hmm there are none that I can think of. I have posted the log down below.

AJ

Anonymous UUID: 1796E383-64A4-A7F8-5E8E-96ADA4B064E8

Fri Feb 15 22:06:06 2019

*** Panic Report ***
panic(cpu 2 caller 0xffffff80056b8a8f): initproc exited -- exit reason namespace 2 subcode 0xa description: none

uuid info:
0x110bca000 uuid = <3eba447f-a546-366b-b302-8dc3b21a3e30>
0x10d040000 uuid = <ae67e27b-133c-3e19-b3e1-d8151233254d>

Thread 1 crashed

RAX: 0x0000000000000000, RBX: 0x000000010d08e060, RCX: 0x000000010d08b000, RDX: 0x000000010d08e080
RSP: 0x0000700004212300, RBP: 0x00007000042123a0, RSI: 0x000000010d08e070, RDI: 0x000000010d040000
R8: 0x000000010d040ae8, R9: 0x000000000000000e, R10: 0x0000000000000010, R11: 0x0000000000000206
R12: 0x0000000100010c26, R13: 0x0000000000001ea8, R14: 0x000000010d090728, R15: 0x000000010d040000
RFL: 0x0000000000010246, RIP: 0x00007fff7d9fb647, CS: 0x000000000000002b, SS: 0x0000000000000023

Thread 0: 0xffffff80180fb880
0x00007fff7db3a0a2
0x00007fff7d9be8a0
0x0000000000000000

Thread 1: 0xffffff801fe532a0
0x00007fff7d9fb647
0x00007fff7d9fb4cd
0x00007fff7d9fb397
0x00007fff7da5ae74
0x000000010d050c26
0x000000010d050261
0x00007fff7d9aedcf
0x00007fff7d9b15dc
0x00007fff7d9c08ed
0x00007fff7d9b4fc9
0x00007fff7d9b5bdc
0x00007fff7d9be090
0x00007fff7dbef60b
0x00007fff7dbef405
0x0000000000070507

Thread 2: 0xffffff8021868440
0x00007fff7dbef3f8

Thread 3: 0xffffff801fe55610
0x00007fff7db37b6a
0x00007fff7dbef405
0x0000002400001200


Mac OS version:
18D109

Kernel version:
Darwin Kernel Version 18.2.0: Thu Dec 20 20:46:53 PST 2018; root:xnu-4903.241.1~1/RELEASE_X86_64
Kernel UUID: 1970B070-E53F-3178-83F3-1B95FA340695
System model name: iMac13,1 (Mac-00BE6ED71E35EB86)

EOF
Model: iMac13,1, BootROM 281.0.0.0.0, 4 processors, Intel Core i5, 2.7 GHz, 8 GB, SMC 2.9f5
Graphics: NVIDIA GeForce GT 640M, NVIDIA GeForce GT 640M, PCIe
Memory Module: BANK 0/DIMM0, 4 GB, DDR3, 1600 MHz, 0x802C, 0x31364A544635313236344A485A3147364D32
Memory Module: BANK 1/DIMM0, 4 GB, DDR3, 1600 MHz, 0x802C, 0x31364A544635313236344A485A3147364D32
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0xF4), Broadcom BCM43xx 1.0 (7.21.190.32 AirPortDriverBrcm4360-1315.1)
Bluetooth: Version 6.0.10f1, 3 services, 27 devices, 1 incoming serial ports
Network Service: Wi-Fi, AirPort, en1
Serial ATA Device: APPLE HDD HTS541010A9E662, 1 TB
USB Device: USB 2.0 Bus
USB Device: Hub
USB Device: Hub
USB Device: BRCM20702 Hub
USB Device: Bluetooth USB Host Controller
USB Device: USB 2.0 Bus
USB Device: Hub
USB Device: FaceTime HD Camera (Built-in)
USB Device: USB 3.0 Bus
USB Device: Composite Device
Thunderbolt Bus: iMac, Apple Inc., 23.4
​

 

[nambuccaheadsau]

What are all the USB hubs and devices and are they attached all the time?

 

[_.adamjames._]

What are all the USB hubs and devices and are they attached all the time?

I’m not quite sure what they are as there’s else nothing connected. All that’s connected is the 2 Thunderbolt cables going to the external displays and the USB 3.0 cable going to the external caddy with the SSD in.

 

[smithrh]

I’m not quite sure what they are as there’s else nothing connected. All that’s connected is the 2 Thunderbolt cables going to the external displays and the USB 3.0 cable going to the external caddy with the SSD in.

Can't help you with specifics to you, other than to tell you that I've very happily running a 2012 27" iMac from external SSD (Thunderbolt in my case) for years - so there's a positive data point.

SSDs do fail. I've had a Samsung fail within a week - keep that in mind.

If you have some other way of testing your SSD, you might try that.

 

[_.adamjames._]

Can't help you with specifics to you, other than to tell you that I've very happily running a 2012 27" iMac from external SSD (Thunderbolt in my case) for years - so there's a positive data point.

SSDs do fail. I've had a Samsung fail within a week - keep that in mind.

If you have some other way of testing your SSD, you might try that.

Have just pasted the first part of the kernel panic into google, and found a couple of forum posts suggesting that disabling “Put hard disks to sleep when possible,” stopped them from experiencing kernel panics, so I have tried that. Will keep an eye on it and see how it goes.

I’m hoping that may have been the problem. If not I will also try resetting the PRAM and SMC and seeing if that helps. Hopefully trying out one of these solutions will solve the issue.

If that fails then I will try formatting the SSD and using it in my Windows machine to test it. I’m really hoping that the SSD isn’t ‘duff’ or that I don’t have to rip the Mac apart to fit the SSD internally.... (would be an excuse to upgrade the RAM though).

Kind of intrigued as to what all those USB hubs are that nambuccaheadsau pointed out are.

 

[mikehalloran]

What OS?

Really, a 2012 should have that 850 on the inside. Takes less than an hour for an experienced tech to install and it's a pretty easy DIY. You will need the OWC temp sensor and a bracket—together about $50.

As both busses are SATA III, there's no advantage to installing an NVMe blade also.

 

[_.adamjames._]

What OS?

Really, a 2012 should have that 850 on the inside. Takes less than an hour for an experienced tech to install and it's a pretty easy DIY. You will need the OWC temp sensor and a bracket—together about $50.

As both busses are SATA III, there's no advantage to installing an NVMe blade also.

Hi Mike,

It’s running Mojave (10.14.3). It’s been running for 3 hours now since I disabled purring hard disks to sleep and so far it’s not gone into a panic yet.

I did think about doing it myself at the time but after reading around I read that the temp sensor can be fiddly, and sometimes heat is needed to soften the adhesive and I’m just wary of damaging the LCD. I’m thinking it would be a good chance to upgrade the RAM though at the same time.

AJ

 

[kwikdeth]

its a lot more likely to be the result of the USB caddy/case or cable than it is to be the drive itself.
in my own personal experience those fail much more often than the drive itself

 

[Schtibbie]

I was just commenting about a similar issue on another thread. My own system with external SSD (no caddy, just regular external drive) isn’t panicking, but I did find that if I open too many programs or tabs and run out of my 8 gigs of ram, it will freeze up solid. This is because apparently Mojave (and High Sierra before it) don’t properly set up the swap VM partition on external boot drives, so no swap is possible. I found forum posts on other sites about it but it’s unclear what the non-hacker was is to solve it or if Apple will fix.

Do you show any swap bytes in Activity Monitor ever? Mine stays pegged at 0 bytes no matter how bad the memory pressure is.

 

[Fishrrman]

OP wrote:
"Have just pasted the first part of the kernel panic into google, and found a couple of forum posts suggesting that disabling “Put hard disks to sleep when possible,” stopped them from experiencing kernel panics, so I have tried that. Will keep an eye on it and see how it goes."

You DO NOT want to "put hard disks to sleep" -- there is the possibility that the computer will "drop the connection" to the boot SSD and that could cause trouble.

I suggest you go to your energy saver pref pane and set it up this way:
1. Computer sleep -- set this to NEVER
2. Display sleep -- set this wherever you want
3. Put hard disks to sleep when possible -- UN check
4. Enable power nap -- UN check

I've been booting and running my 2012 Mini for SIX YEARS+ this way, no crashes when waking from sleep...

 

[_.adamjames._]

Hi all, and thank you for your suggestions.

So, as Fishrrman just posted, and the other forum I looked at last night suggested disabling 'put hard disks to sleep,' I tried that. It idled away all night wiithout any issues, and I ran disk checks and was using Firefox, MS Powerpoint and Spotify all morning without any issues.

So, this afternoon I decided to check the swap as Schtibbie suggsted, and found that it was indeed showing as 0 bytes even though the memory pressure was quite high. So I mounted the swap partition using: "sudo diskutil mount -mountPoint /private/var/vm disk2s4"

After doing so and restarting activity monitor, my swap was then being used, and I had no issues for around 3 hours.

Then, I came to going into Lightroom to merge quite a hefty panorama together (whilst keeping an eye on the RAM and Swap usage...all looked fine), and it merged together no issues, and then I worked into a few more images. Then, I zoomed into part of a picture to make adjustments, so opened the whole image on an external monitor using lightroom's multiple display feature - then loe and behold, it locked up for a few seconds, then turned off. Though this time, once it tried restarting, it just froze on the white screen and did not do the chime. So I turned it off using the power button and turned it back on again and it booted up fine, however this time it did not give me an error report upon login and I cannot find one in Console.

I have just been back into lightroom and done the same, and it did not lock up on me this time. The past couple of times it has locked up before that, it was either just idling and I'd come back to find it had restarted and had a kernel panic, or I was only browsing on firefox and going through files in Finder - so I'm at a bit of a loose end as to what might be causing thi. I'm thinking it's highly unlikely to be a speciic piece of software causing this since it's now happened in multiple applications?

AJ

 

[mikehalloran]

after reading around I read that the temp sensor can be fiddly,

About that...

Nothing like "reading around" to become misinformed. Here's the this about that:

The OE hard drive has a temp sensor that plugs in. It only works with certain HHDs from the same manufacturer that are compatible, Seagate or WD — not any HHD but one that is compatible. The Seagate and WD are not interchangeable. This is removed when you install an SSD and is replaced by the OWC temp sensor or the fans will roar at top speed.

There is a software solution but it roars on startup till the extension kicks in and it forces you to control the fans manually. Both are unacceptable in my book.

Nothing fiddly about the OWC part. It is attached with tape to the outside and can be used with any HHD or SSD. No fans roaring on startup. Automatic temp/fan control.

Your 2012 will run much cooler with your 850 mounted inside and that spinning heat pump gone. Your internal components, especially the GPU will last far longer. Fewer repairs. Oh yea, it will boot and run a lot faster. There are no downsides to doing this.

If you are afraid of doing the job yourself, pay someone to have it done.

Tip: when putting it together, use a few strips of masking or blue paper tape to hold it together. Run the machine to make sure everything works. Now use the foam tape to reassemble properly.

In 2015, Apple went with a slower, cooler HHD on the fusion models to lessen warranty and reliability issues.

 

[_.adamjames._]

Thanks for your help Mike, sounds like a fairly simple job to do actually.

A bit of a development, crashed AGAIN today but this time the log had a bit more information in it:

Anonymous UUID: 1796E383-64A4-A7F8-5E8E-96ADA4B064E8

Sun Feb 17 13:30:03 2019

*** Panic Report ***
panic(cpu 3 caller 0xffffff802b8da29d): Kernel trap at 0xffffff7fac7fb21a, type 14=page fault, registers:
CR0: 0x0000000080010033, CR2: 0xffffff8116a7b140, CR3: 0x000000002fb8f000, CR4: 0x00000000001626e0
RAX: 0xffffff8116a7b040, RBX: 0xffffff8042ba1000, RCX: 0x000000005f07e6be, RDX: 0x0000000000003c42
RSP: 0xffffff812d79bd90, RBP: 0xffffff812d79bdb0, RSI: 0xffffff80492b0400, RDI: 0xffffff8042ba1000
R8: 0xffffff803fa21cf8, R9: 0x0000000000000013, R10: 0xffffff802c09eb68, R11: 0x0000000000000040
R12: 0x00000001000006c7, R13: 0xffffff802be29670, R14: 0xffffff80492b0400, R15: 0xffffff8043d278a0
RFL: 0x0000000000010246, RIP: 0xffffff7fac7fb21a, CS: 0x0000000000000008, SS: 0x0000000000000000
Fault CR2: 0xffffff8116a7b140, Error code: 0x0000000000000000, Fault CPU: 0x3, PL: 0, VF: 10

Backtrace (CPU 3), Frame : Return Address
0xffffff812d79b860 : 0xffffff802b7aeb0d
0xffffff812d79b8b0 : 0xffffff802b8e8653
0xffffff812d79b8f0 : 0xffffff802b8da07a
0xffffff812d79b960 : 0xffffff802b75bca0
0xffffff812d79b980 : 0xffffff802b7ae527
0xffffff812d79baa0 : 0xffffff802b7ae373
0xffffff812d79bb10 : 0xffffff802b8da29d
0xffffff812d79bc80 : 0xffffff802b75bca0
0xffffff812d79bca0 : 0xffffff7fac7fb21a
0xffffff812d79bdb0 : 0xffffff7fac8f50db
0xffffff812d79bdd0 : 0xffffff7fac801586
0xffffff812d79be10 : 0xffffff7fac80498a
0xffffff812d79be30 : 0xffffff7fac802acd
0xffffff812d79be60 : 0xffffff802be2977d
0xffffff812d79bea0 : 0xffffff802be5582e
0xffffff812d79bee0 : 0xffffff802be28839
0xffffff812d79bf60 : 0xffffff802be33227
0xffffff812d79bfa0 : 0xffffff802b75b0ce
Kernel Extensions in backtrace:
com.apple.iokit.IOAcceleratorFamily2(404.2.2)[3F0DBC5F-414B-379E-8C7B-A2F50B278A2A]@0xffffff7fac7e5000->0xffffff7fac889fff
dependency: com.apple.driver.AppleMobileFileIntegrity(1.0.5)[A2492141-9480-3177-BC7D-455925BB4A2E]@0xffffff7fac79d000
dependency: com.apple.iokit.IOSurface(255.1)[12B5957C-3874-3A96-8FC6-FAC2180790A9]@0xffffff7fac7ba000
dependency: com.apple.iokit.IOPCIFamily(2.9)[5C9A453F-559B-3683-9E81-D288D13A33CE]@0xffffff7fac095000
dependency: com.apple.iokit.IOGraphicsFamily(530.14)[D44517BE-2B53-3BD5-826E-4E78B55E3B73]@0xffffff7fac37d000
dependency: com.apple.iokit.IOReportFamily(47)[5F165AE5-F4F2-3415-857C-34F2462A730E]@0xffffff7fac7de000
com.apple.GeForce(12.0)[1B24BF7A-E3A6-35F8-8222-17A0E863C3D0]@0xffffff7fac89a000->0xffffff7fac935fff
dependency: com.apple.iokit.IOPCIFamily(2.9)[5C9A453F-559B-3683-9E81-D288D13A33CE]@0xffffff7fac095000
dependency: com.apple.iokit.IONDRVSupport(530)[693B770C-4748-33DC-B497-CF8C103DDD0E]@0xffffff7fac3d5000
dependency: com.apple.nvidia.driver.NVDAResman(12.0.0)[AE94AB7B-ECE1-31E6-8165-08FF46E8CF81]@0xffffff7fac3f0000
dependency: com.apple.iokit.IOGraphicsFamily(530.14)[D44517BE-2B53-3BD5-826E-4E78B55E3B73]@0xffffff7fac37d000
dependency: com.apple.iokit.IOAcceleratorFamily2(404.2.2)[3F0DBC5F-414B-379E-8C7B-A2F50B278A2A]@0xffffff7fac7e5000

BSD process name corresponding to current thread: kernel_task

Mac OS version:
18D109

Kernel version:
Darwin Kernel Version 18.2.0: Thu Dec 20 20:46:53 PST 2018; root:xnu-4903.241.1~1/RELEASE_X86_64
Kernel UUID: 1970B070-E53F-3178-83F3-1B95FA340695
Kernel slide: 0x000000002b400000
Kernel text base: 0xffffff802b600000
__HIB text base: 0xffffff802b500000
System model name: iMac13,1 (Mac-00BE6ED71E35EB86)

System uptime in nanoseconds: 66256994047891
last loaded kext at 46763543230: com.apple.filesystems.smbfs 3.3.1 (addr 0xffffff7fae646000, size 442368)
last unloaded kext at 420755143643: com.apple.driver.AppleUSBMergeNub 900.4.2 (addr 0xffffff7fae447000, size 12288)
loaded kexts:
com.apple.filesystems.smbfs 3.3.1
com.apple.filesystems.msdosfs 1.10
com.apple.driver.AppleBluetoothMultitouch 96
com.apple.driver.AudioAUUC 1.70
com.apple.driver.AppleHWSensor 1.9.5d0
com.apple.fileutil 18.306.12
com.apple.driver.X86PlatformShim 1.0.0
com.apple.driver.AGPM 110.23.46
com.apple.driver.ApplePlatformEnabler 2.7.0d0
com.apple.filesystems.autofs 3.0
com.apple.driver.AppleMikeyHIDDriver 131
com.apple.driver.AppleMikeyDriver 282.10
com.apple.AGDCPluginDisplayMetrics 3.28.4
com.apple.driver.AppleHDA 282.10
com.apple.driver.AppleHV 1
com.apple.iokit.IOUserEthernet 1.0.1
com.apple.iokit.IOBluetoothSerialManager 6.0.10f1
com.apple.driver.AppleUpstreamUserClient 3.6.5
com.apple.GeForce 12.0.0
com.apple.driver.eficheck 1
com.apple.driver.pmtelemetry 1
com.apple.driver.AppleIntelHD4000Graphics 12.0.4
com.apple.driver.AppleThunderboltIP 3.1.2
com.apple.Dont_Steal_Mac_OS_X 7.0.0
com.apple.driver.AppleLPC 3.1
com.apple.driver.AppleSMCLMU 212
com.apple.driver.AppleMCCSControl 1.5.6
com.apple.driver.AppleOSXWatchdog 1
com.apple.driver.AppleIntelFramebufferCapri 12.0.4
com.apple.driver.AppleIntelSlowAdaptiveClocking 4.0.0
com.apple.driver.AppleVirtIO 2.1.3
com.apple.filesystems.hfs.kext 407.200.4
com.apple.AppleFSCompression.AppleFSCompressionTypeDataless 1.0.0d1
com.apple.BootCache 40
com.apple.AppleFSCompression.AppleFSCompressionTypeZlib 1.0.0
com.apple.AppleSystemPolicy 1.0
com.apple.filesystems.apfs 945.241.4
com.apple.driver.AppleSDXC 1.7.6
com.apple.private.KextAudit 1.0
com.apple.iokit.AppleBCM5701Ethernet 10.3.3
com.apple.driver.AirPort.Brcm4360 1400.1.1
com.apple.driver.AppleAHCIPort 329.200.2
com.apple.driver.AppleRTC 2.0
com.apple.driver.AppleACPIButtons 6.1
com.apple.driver.AppleHPET 1.8
com.apple.driver.AppleSMBIOS 2.1
com.apple.driver.AppleACPIEC 6.1
com.apple.driver.AppleAPIC 1.7
com.apple.driver.AppleIntelCPUPowerManagementClient 220.0.0
com.apple.nke.applicationfirewall 190
com.apple.security.TMSafetyNet 8
com.apple.driver.AppleIntelCPUPowerManagement 220.0.0
com.apple.driver.AppleBluetoothHIDKeyboard 208
com.apple.driver.AppleHIDKeyboard 208
com.apple.driver.IOBluetoothHIDDriver 6.0.10f1
com.apple.driver.AppleMultitouchDriver 2410.5
com.apple.driver.AppleInputDeviceSupport 2410.2
com.apple.kext.triggers 1.0
com.apple.driver.DspFuncLib 282.10
com.apple.kext.OSvKernDSPLib 527
com.apple.iokit.IOAVBFamily 710.1
com.apple.plugin.IOgPTPPlugin 700.7
com.apple.driver.AppleSSE 1.0
com.apple.nvidia.driver.NVDAGK100Hal 12.0.0
com.apple.nvidia.driver.NVDAResman 12.0.0
com.apple.iokit.IONDRVSupport 530
com.apple.driver.AppleHDAController 282.10
com.apple.iokit.IOHDAFamily 282.10
com.apple.driver.AppleSMBusPCI 1.0.14d1
com.apple.driver.AppleSMBusController 1.0.18d1
com.apple.driver.X86PlatformPlugin 1.0.0
com.apple.driver.IOPlatformPluginFamily 6.0.0d8
com.apple.iokit.IOAcceleratorFamily2 404.2.2
com.apple.iokit.IOSurface 255.1
com.apple.driver.AppleThunderboltEDMSink 4.2.0
com.apple.AppleGPUWrangler 3.28.4
com.apple.AppleGraphicsDeviceControl 3.28.4
com.apple.iokit.IOGraphicsFamily 530.14
com.apple.iokit.IOSlowAdaptiveClockingFamily 1.0.0
com.apple.iokit.BroadcomBluetoothHostControllerUSBTransport 6.0.10f1
com.apple.iokit.IOBluetoothHostControllerUSBTransport 6.0.10f1
com.apple.iokit.IOBluetoothHostControllerTransport 6.0.10f1
com.apple.iokit.IOBluetoothFamily 6.0.10f1
com.apple.iokit.IOAudioFamily 206.5
com.apple.vecLib.kext 1.2.0
com.apple.driver.usb.networking 5.0.0
com.apple.driver.usb.AppleUSBHostCompositeDevice 1.2
com.apple.driver.usb.AppleUSBHub 1.2
com.apple.iokit.IOSerialFamily 11
com.apple.filesystems.hfs.encodings.kext 1
com.apple.driver.AppleThunderboltDPInAdapter 5.5.8
com.apple.driver.AppleThunderboltDPOutAdapter 5.5.8
com.apple.driver.AppleThunderboltDPAdapterFamily 5.5.8
com.apple.driver.AppleThunderboltPCIDownAdapter 2.1.4
com.apple.iokit.IOAHCIBlockStorage 301.200.2
com.apple.driver.AppleThunderboltNHI 4.7.6
com.apple.iokit.IOThunderboltFamily 6.8.1
com.apple.iokit.IOEthernetAVBController 1.1.0
com.apple.iokit.IO80211Family 1200.12.2
com.apple.driver.mDNSOffloadUserClient 1.0.1b8
com.apple.driver.corecapture 1.0.4
com.apple.iokit.IOAHCIFamily 288
com.apple.driver.usb.AppleUSBHostPacketFilter 1.0
com.apple.iokit.IOUSBFamily 900.4.2
com.apple.driver.usb.AppleUSBEHCIPCI 1.2
com.apple.driver.usb.AppleUSBEHCI 1.2
com.apple.driver.usb.AppleUSBXHCIPCI 1.2
com.apple.driver.usb.AppleUSBXHCI 1.2
com.apple.driver.AppleUSBHostMergeProperties 1.2
com.apple.driver.AppleEFINVRAM 2.1
com.apple.driver.AppleEFIRuntime 2.1
com.apple.iokit.IOSMBusFamily 1.1
com.apple.iokit.IOHIDFamily 2.0.0
com.apple.security.quarantine 3
com.apple.security.sandbox 300.0
com.apple.kext.AppleMatch 1.0.0d1
com.apple.driver.DiskImages 493.0.0
com.apple.driver.AppleFDEKeyStore 28.30
com.apple.driver.AppleEffaceableStorage 1.0
com.apple.driver.AppleKeyStore 2
com.apple.driver.AppleUSBTDM 456.230.1
com.apple.driver.AppleMobileFileIntegrity 1.0.5
com.apple.kext.CoreTrust 1
com.apple.iokit.IOUSBMassStorageDriver 145.200.2
com.apple.iokit.IOSCSIBlockCommandsDevice 408.200.1
com.apple.iokit.IOSCSIArchitectureModelFamily 408.200.1
com.apple.iokit.IOStorageFamily 2.1
com.apple.driver.AppleCredentialManager 1.0
com.apple.driver.KernelRelayHost 1
com.apple.iokit.IOUSBHostFamily 1.2
com.apple.driver.usb.AppleUSBCommon 1.0
com.apple.driver.AppleBusPowerController 1.0
com.apple.driver.AppleSEPManager 1.0.1
com.apple.driver.IOSlaveProcessor 1
com.apple.iokit.IOTimeSyncFamily 700.7
com.apple.iokit.IONetworkingFamily 3.4
com.apple.iokit.IOReportFamily 47
com.apple.driver.AppleACPIPlatform 6.1
com.apple.driver.AppleSMC 3.1.9
com.apple.iokit.IOPCIFamily 2.9
com.apple.iokit.IOACPIFamily 1.4
com.apple.kec.pthread 1
com.apple.kec.Libm 1
com.apple.kec.corecrypto 1.0

EOF
Model: iMac13,1, BootROM 281.0.0.0.0, 4 processors, Intel Core i5, 2.7 GHz, 8 GB, SMC 2.9f5
Graphics: NVIDIA GeForce GT 640M, NVIDIA GeForce GT 640M, PCIe
Memory Module: BANK 0/DIMM0, 4 GB, DDR3, 1600 MHz, 0x802C, 0x31364A544635313236344A485A3147364D32
Memory Module: BANK 1/DIMM0, 4 GB, DDR3, 1600 MHz, 0x802C, 0x31364A544635313236344A485A3147364D32
AirPort: spairport_wireless_card_type_airport_extreme (0x14E4, 0xF4), Broadcom BCM43xx 1.0 (7.21.190.32 AirPortDriverBrcm4360-1315.1)
Bluetooth: Version 6.0.10f1, 3 services, 27 devices, 1 incoming serial ports
Network Service: Wi-Fi, AirPort, en1
Serial ATA Device: APPLE HDD HTS541010A9E662, 1 TB
USB Device: USB 2.0 Bus
USB Device: Hub
USB Device: FaceTime HD Camera (Built-in)
USB Device: USB 2.0 Bus
USB Device: Hub
USB Device: Hub
USB Device: BRCM20702 Hub
USB Device: Bluetooth USB Host Controller
USB Device: USB 3.0 Bus
USB Device: Composite Device
Thunderbolt Bus: iMac, Apple Inc., 23.4
​

 

[Schtibbie]

...
So, this afternoon I decided to check the swap as Schtibbie suggsted, and found that it was indeed showing as 0 bytes even though the memory pressure was quite high. So I mounted the swap partition using: "sudo diskutil mount -mountPoint /private/var/vm disk2s4"

After doing so and restarting activity monitor, my swap was then being used, and I had no issues for around 3 hours.
...

AJ

Yeah, I saw the same mount instructions for /private/var/vm by Googling, but... Apparently that doesn't survive reboots, and the other solutions I found really started to seem to me like "Apple needs to fix Mojave to actually, you know, MOUNT THE VM PARTITION PROPERLY". I shouldn't have to sudo crap to make my OS work unless it's my hobby or something.