On Sun, 2018-03-11 at 06:33 +0200, Jaco Kroon wrote: > crowsnest ~ # find /sys -name sdm > /sys/kernel/debug/block/sdm > /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/host0/port-0:0/expander-0:0/port-0:0:0/expander-0:1/port-0:1:0/end_device-0:1:0/target0:0:13/0:0:13:0/block/sdm > /sys/class/block/sdm > /sys/block/sdm > > > lspci > > crowsnest ~ # lspci > [ ... ] > 01:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic > SAS3008 PCI-Express Fusion-MPT SAS-3 (rev 02) > [ ... ] Hi Jaco, Recently a bug fix for the mq-deadline scheduler was posted but I don't think that that patch will change the behavior on your setup since you are not using ZBC disks. See also "mq-deadline: Make sure to always unlock zones" (https://marc.info/?l=linux-block&m=151983933714492). Did I see correctly that /dev/sdm is behind a MPT SAS controller? You may want to contact the authors of this driver and Cc the linux-scsi mailing list. Sorry but I'm not familiar with the mpt3sas driver myself. Bart.