VB 6.1 Ubuntu 19.10 ZFS IO error if disk Dynamically Allocated

[MasterCATZ]

Ubuntu 19.10 Kernel 5.4.3-050403-generic VirtualBox 6.1

I tried installing Windows 10 on a 50 gig VDI Dynamically Allocated and I kept getting data corruption / freezes while it was installing to my zfspool

using 64 gig ram AMD Ryzen 9 3900x and 16x HDD in 3 way zfs mirror

after trying all other settings and 20+ install attempts what seemed to work was using a fixed size disk during creation

[mpack]

Whether a disk is dynamically allocated or not can make no possible difference to a guest. The capacity the guest sees is the same either way.

"Dynamic" does not mean magically expanding drive, it means that allocation is postponed until the guest writes to the drive sectors in question. At which point the only credible error is running out of space on the host partition, or some other kind of host I/O error.

Hence: look elsewhere for your problem.

[socratis]

what seemed to work was using a fixed size disk during creation

Do you have logs from both attempts? Fixed vs Dynamic? There is a slight chance that the constant increase of a dynamic VDI might not be "liked" by the ZFSpool. ZFS has had issues in the past...

And I would definitely look in the ZFS/system logs...