Kernel Panics in Catalina 10.15.4/Thunderbay 4

I do not know. Perhaps it is the RAM, I noticed you had 24GB of RAM, perhaps you have mixed RAM and that is triggering something?

I do not have any experience with this dart=0 setting, I know it slows down RAM because is eliminates some cacheing, but it should not cause issues. There could be something else going on.

Fortunately we are not getting this from other users (yet), and I hope your case is unique.

I purchased this iMac 27" model late 15, brand new in he beginning of 2016 with 2 x 4GB RAM, within two weeks I added 2x8GB off brand RAM to it and it has ran fine since then. I cannot imagine this woud be the problem.

But, I will run a few memory tests this weekend.

I think I saw in the support file you sent, you have a disk with 328 reallocated sectors. that can easily cause kernel panics, and the panic suggests the crash was in the file system.

Joining this thread because I've been going out of my mind with this... I get no less than one kernel panic per day since 10.15.4 while using SoftRAID XT v 5.8.3 and Driver v 5.8.3... it's been so bad, I've considered dumping it and just using the built-in macOS RAID and forgetting about redundancy. I really hope this gets resolved soon because these disks are on my always-on backup/Plex/surveillance machine so needless to say, this absolutely sucks.

Did you see the link to the blogpost with the workaround? At least that gets you by.

We are pretty sure 10.15.5 will have a solution but it is not in the beta 2 version.

And yes it sucks!!!

I think I saw in the support file you sent, you have a disk with 328 reallocated sectors. that can easily cause kernel panics, and the panic suggests the crash was in the file system.

I had a big fat crash last week (HFS overwritten on a USB OWC case and I changed the disks to a Thunderbolt OWC case), I had to re-certify all the disks, including the one with bad sectors so I am pretty sure the bad sectors are not used. Replacing the bad-sector disk is on my radar of course.

There are two points:
When a disk starts reallocating sectors, this means it is failing.
Second, a disk like this one has a large area which cannot be easily read, hence it is "retrying" sectors, which can cause the drive to time-out for up to two minutes, which will crash OS X.

Not to say the crash was not caused by something else, but in my experience, a drive with even one bad sector starts to crash the CPU.

There are two points:
When a disk starts reallocating sectors, this means it is failing.
Second, a disk like this one has a large area which cannot be easily read, hence it is "retrying" sectors, which can cause the drive to time-out for up to two minutes, which will crash OS X.

Not to say the crash was not caused by something else, but in my experience, a drive with even one bad sector starts to crash the CPU.

ok, i will replace the disk.

I do not know. Perhaps it is the RAM, I noticed you had 24GB of RAM, perhaps you have mixed RAM and that is triggering something?

I do not have any experience with this dart=0 setting, I know it slows down RAM because is eliminates some cacheing, but it should not cause issues. There could be something else going on.

Fortunately we are not getting this from other users (yet), and I hope your case is unique.

I purchased this iMac 27" model late 15, brand new in he beginning of 2016 with 2 x 4GB RAM, within two weeks I added 2x8GB off brand RAM to it and it has ran fine since then. I cannot imagine this woud be the problem.

But, I will run a few memory tests this weekend.

I ran a memtest86 memory test (4 times) for about 6 hours and I had no errors.

Can you guys check if System Preferences -> Energy Saver -> Put hard disk to sleep when possible is unchecked? If it is not, please uncheck it and try your tests again. This panic is bubbling up from the power management subsystem, so this may be a possible workaround.

We generally have this unchecked, but will investigate this setting and see if there are any identifiable issues in this.

Joining this thread because I've been going out of my mind with this... I get no less than one kernel panic per day since 10.15.4 while using SoftRAID XT v 5.8.3 and Driver v 5.8.3... it's been so bad, I've considered dumping it and just using the built-in macOS RAID and forgetting about redundancy. I really hope this gets resolved soon because these disks are on my always-on backup/Plex/surveillance machine so needless to say, this absolutely sucks.

I made those changes and I've been up for a few days now with no reboots/crashes, so this fix is working. Can't wait until this all gets sorted out and can revert those changes made to the OS.

Agreed!

The fix is not yet in 10.15.5 beta 2. We are keeping our fingers crossed it makes it in!

There are two points:
When a disk starts reallocating sectors, this means it is failing.
Second, a disk like this one has a large area which cannot be easily read, hence it is "retrying" sectors, which can cause the drive to time-out for up to two minutes, which will crash OS X.

Not to say the crash was not caused by something else, but in my experience, a drive with even one bad sector starts to crash the CPU.

ok, i will replace the disk.

Yesterday new disk (4TB) certified, swapped out with the disk with bad sectors and rebuild in the RAID 5 volume. No reboots in the last two days.

There are two points:
When a disk starts reallocating sectors, this means it is failing.
Second, a disk like this one has a large area which cannot be easily read, hence it is "retrying" sectors, which can cause the drive to time-out for up to two minutes, which will crash OS X.

Not to say the crash was not caused by something else, but in my experience, a drive with even one bad sector starts to crash the CPU.

ok, i will replace the disk.

Yesterday new disk (4TB) certified, swapped out with the disk with bad sectors and rebuild in the RAID 5 volume. No reboots in the last two days.

had another reboot this morning. I am hoping for a fix soon

So are we. No news on the next beta of 10.15.5. Hoping it will have he fix in it.