Qbittorrent 4.6.0 takes a long time to shut down

[AvangionQ]

Every once in a while Qbittorrent 4.6.0 slows to a crawl and stops transferring data efficiently.
I have 8000+ loaded torrents and go from over 100mbps to less than 100kbps in data transfers.
When I shut down 4.6.0 to start it up again, the shutdown process takes 9GB RAM and 10 minutes.
The whole time, I see the HDD going between 40MBps to 100MBps, so it's doing something fast.
I'm not sure what's going on. Is there any log file or anything of the sort I can upload here?

[Gripweed107]

What brand/model of hard drives are you using? It sounds like they are using SMR technology. More space, less reliable.

[AvangionQ]

I have no idea how to even tell the difference. Can you see this Speccy summary image?

Intel 256GB SSD main drive
Toshiba 5TB internals (x2)
Western Digital 4TB internal
Seagate 4TB external
Seagate 5TB external
Seagate 8TB external x2
Western Digital 2TB external x2
Western Digital 8TB external

All hard drives are working normally.

[Gripweed107]

The best that I could come up with based on a short amount of research is:

Toshiba HDWE150  CMR
WD 1230  SMR
Seagate ST4000DM000 CMR
WD Elements 25A3  SMR

Others that are listed are just USB devices and so I'm not sure what actual HDDs they are using. Anyway, some of the drives listed are SMR and could be the cause of your problems depending on whether they are being used by Qbittorrent. In case you aren't familiar, I suggest Googling "CMR vs SMR".

[bob2306]

The problem with SMR is the slow write speed and hiatuses that occur with small random writes. This is irrelevant for the drives that store your completed torrents, but it may have an effect on downloading torrents.

I suspect your problem is due to saving resume data, which is done periodically and at shutdown. I've not tried it myself, but I've heard that switching from fast-resume files to SQLite in advanced settings can make a big difference.