snapraid sync -h or snapraid scrub -p new will result in thousands of errors after upgrading OMV3 to 4 or 5. Through a series of tests, I've eliminated any possible hardware issues, and can reliably replicate the issue by only installing a newer version of the software. If there was a hardware issue, I should see errors on all software versions, but I do not.
OMV 3 with snapraid 11.1 = NO ERRORS (tested multiple times to make sure)
Fresh install of OMV 4 or 5 with snapraid plugin (v11.3) = thousands of errors with just 2 test files.
OMV 4 or 5 with snapraid 11.1(manual snapraid install, no plugin) = few errors, much better than v11.3 but still broken. snapraid 11.1 only works on OMV3.
snapraid sync -h
snapraid scrub -p new
When I encountered the issue after upgrading, first thing I did was test my hardware. Note, before I upgraded, OMV3 w snapraid 11.1 had been running on this system 24x7 for over 3 years with 0 issues.
Hardware stability tests:
on problem machine ran these tests
1. 17hr 8 full pass test with memtest86+ - no errors
2. prime95 small fft's 4hrs - no error (max cpu temp 57c)
3. prime95 blend test 4hrs - no errors
4. SMART extended test on all drives - no errors
Tested on 2 different machines, Core i5 4590 works, Core2quad q9550 does not.
Each OMV version was fresh installed, not upgraded.
Used 3 drives for tests, 2 data, 1 parity.
2 different video files (1 on each data drive)
Content and parity files deleted between test runs, data untouched between tests.
1. ran snapraid sync -h
2. ran snapraid scrub -p new
OMV 3 with snapraid plugin 3.73 (v11.1) = NO ERRORS (tested multiple times to make sure)
A combination of OMV 4 or 5 with snapraid 11.3 = thousands of errors with just 2 test files. (errors on core2quad machine only)
OMV 4 or 5 with snapraid 11.1(manual snapraid install, no plugin) = few errors, much better than v11.3 but still broken. snapraid 11.1 only works if on OMV3. (errors on core2quad machine only)
Issue is specific to my hardware layout (LGA775 Core2quad q9550, P45 chipset), tested on newer hardware (HP z230 corei5 4590 C226 chipset) and there were no errors. Also, I moved 2 of the sata controllers from the problem machine to the newer hardware testbed, with test drives connected to these controllers, (to rule out the sata controllers) and used the same drives throughout all tests on both machines. I would guess the issue could probably be replicated with the same CPU / chipset as my problem machine.
I've proven the issue can be predictably replicated just by upgrading the software from OMV 3 w/snapraid 11.1 to OMV 4 or 5 w/snapraid 11.3.
Again, OMV 3 w/snapraid 11.1 works with no errors, I've put my 12TB of data back on OMV3 for now and had to resync the array.
Problem machine System specs:
Snapaid plugin 5.0.5 (snapraid V11.3)
Motherboard: Gigabyte GA-EP45-UD3P (LGA775 P45 chipset)
CPU: Core2quad q9550
Memory: OCZ2N800SR4GK 4x2GB sticks (DDR2 800 5-4-4-15 2.1v)
PCIE Sata Cards: 4x startech PEXESAT3221 2 port sata cards with ASM1062 controller
Power Supply: OCZ750FTY - Fatal1ty Gaming Series 750 Watt 80+ Bronze
Parity Drives: 2x Fantom GF3B8000EU (8TB drives connected via ESATA)
Data Drives: 9 drives mixed 1TB, 2TB, 4TB, 6TB... mostly all WD, one Hitachi, can provide full details if needed.