Hi everyone,
I'm gonna try to explain the situation the best i can, given im just a casual unRAID user, with no special setup, just using Plex, Piehole, Deluge, DuckDNS, OpenVPN (yes i know...) and a couple VMs.
Any help or at least an explanation is very welcome!
Firstly, my unraid setup:
CPU - i7 8700k
mobo - GIGABYTE Z390 M
RAM - 32GB 3200mhz CL 16 Crucial Ballistix
PSU - Corsair SF600 Gold
HBA - LSI 9211 -8i IT mode, with 2x SAS to 4xSATA
HDDs are as follows:
PARITY disk - 1x Toshiba 16TB (MG08ACA16TE)
DATA disk - 3x Seagate Exos x16 14TB
DATA disk - 2x WD120EMAZ 12TB (WD Elements shucked drives)
DATA disk - 1x WD80EDAZ 8TB (WD Elements shucked drive)
DATA disk - 1x WD Pruple 12TB
The "strange" behavior/problem:
Initially i had 4x Seagate drives but decided to replace them with 4x Toshiba (MG08ACA16TE) drives. When i had first added my Seagate drives, every parity rebuild (each of the Seagates replaced old WD Reds) worked like a charm and started at a constant ~220MB and then slowley worked its way down as it reached the end of the platters, at around ~120MB or something like that.
I then started replacing the Seagate drives with the first Toshiba, but got speeds, ranging from ~150MB to ~190MB. I decided to keep going and finished the rebuild.
But when i got the second Toshiba drive in to replace the second Seagate, my parity rebuild speeds started swinging wildly between ~70MB and ~150MB, but never above ~150MB. Initially i thought the drive was "bad", so i stopped the rebuild 5min in and swapped this Toshiba drive with another Toshiba drive. But i was surprised to see that nothing changed and the rebuild was showing the same behavior with swinging speeds between ~70MB and ~150MB. I dare say, i cant be that unlucky and have two "bad" Tohsiba drives, with the exact same behavior.
After looking around the unRAID forum for a while, i came across a post, someone was recommending to change the following disk settings if using "larger arrays" (not sure what constitutes a "large array", but i thought i might fit the bill):
Tunable (md_num_stripes): 4096
Tunable (md_sync_window): 2048
Tunable (md_sync_thresh): 2000
When checking disk settings, i noticed i only have the first setting available to modify, so i did and changed it to 4096.
After doing this, i started the parity rebuild process again and my speeds are still "swinging" but are now doing it between ~170MB and ~190MB.
If anyone can explain all of this, please do, or give some additional info as to what is going on, that would be very much appreciated! More so, as i have no idea what any of those settings actully "do" and if using them/it creates any problems - sure im happy with the speed bump, but not at any cost.
I've been struggeling with my unRAID ever since i decided to swap the 4TB WD Reds for the 14TB Seagates (a different story...) and now my pain appears to continue with the Toshiba drives and i've, more or less, reached the end of both my technical knowhow and patience and just want to have it stable and working again, with no new behaviours and "odd personality disorders"
I swear, i've been an extremly happy user of unRAID for close to 2 years, until i decided to start "upgrading" Western Digital drives to anything else... im not sure if thats the issue or not but it sure looks like it.
Sorry for the wall of text and as i've said before, any help/info is appreciated!