After 9.3 -> 9.10 upgrade page fault on pool mount

[PC_M@niac]

My config is: Intel Atom D525 + 8Gb RAM, 2x16Gb flash for boot pool and 4x4Tb for main data pool (geli encryption + RAIDZ1).

After system upgrade from 9.3 to 9.10 I can't mount my main pool from web interface and from console.
On "zpool import -o altroot=/mnt main" I got "page fault" error message and system going to reboot.

When I boot from 9.3 snapshot and make import from console "zpool import -o altroot=/mnt main", I see only the first dataset mounted and after 10+ hours of waiting still only the first. On the WebInterface I didn't see any disk/cpu activity and 6.5Gb RAM is free.

I got another flash and install clean FN9.10, but when I trying to import pool, got "page fault" and reboot like on updated system.

What can I try?

 

[m0nkey_]

A page fault typically means you're out of memory.

This is a case of not having enough RAM. Okay, you have 8GB, but you have roughly 16TB storage. The general rule is 1GB RAM for 1TB storage. It also doesn't help your pool is encrypted. The D525 doesn't have AES-NI, which is going to be heavy for the CPU.

 

[PC_M@niac]

Memory is not a deal. I wrote that 6.5Gb is free, and before upgrade all was ok. I didn't use deduplication and set ARC size to 1Gb.
CPU also not a deal. Read/write speed about 20Mb/sec on SMB and 80Mb/sec on iSCSI and it is normal for my tasks (backup and media storage).

I tried per-operation import and found that page fault causes on mounting one of 20+ datasets.

By steps:
1. SSH login
2. geli decrypt (on all 4 HDDs): geli attach -k /root/geli.key /dev/gptid/<drive-guid>
3. pool import without ds automount: zpool import -o altroot=/mnt -N main
4. datasets mount (on all): zfs mount main/<ds-name>

when I got "page fault" on one of datasets, I (after reboot :) ) go thru steps 1-3,
then disable automount of that ds: zfs set canmount=off main/<ds-name>
then reboot and mount all from GUI (except that DS).

Now I started scrub to find out a pool problems (if any): zpool scrub main
Maybe I need to delete and recreate of that dataset, but I hope scrub helps me :)