I have an "interesting" problem today: I have a 4 disk USB 3.1 enclosure, the disks in it are crap (Toshiba N300) so it fails when pushing to much data. When I connect that enclosure to a 5 GBit USB3 port it works fine, if I connect that to a 10 GBit port it fails badly. So: How can I limit the 10 GBit port to negotiate only to 5 GBit to not overload the crappy HDDs? (It's not the cabling, it's the disks, I know because they fail on SATA the same way) #linux #usb #disk
@dunkelstern Can't you rate limit the block devices of disks instead?
@dunkelstern Hm~ I thought that devicemapper had an interposer that does that, but now I can only find dm-delay which isn't helpful here.
@robryk After further thinking it through: No block device throttling would give me nothing as the kernel itself could create high-bandwidth throughput (btrfs rebalance/scrub for example) and cgroups for example cannot throttle that.
@dunkelstern If there was a dm-throttle, it would also throttle everything the fs driver would be doing in its own name (and any kernel thread in general).
@robryk if that's possible it should probably work as the problem is not the usb controller but the disks themselves. Do you know how to do that?