quoted

quoted

I'm not 100% sure about which data you need and where to find  
nr_hw_queues exposed. 

nr_hw_queues is not available on 5.4 kernel via sysfs

it's prob same as count of CPUs in the system

or you can check number of hctxX folders in 
/sys/kernel/debug/block/sdX (need to be root, and debugfs enabled)

root@deadbird:~# ls -d /sys/kernel/debug/block/sdz/hc*
/sys/kernel/debug/block/sdz/hctx0 /sys/kernel/debug/block/sdz/hctx16 
/sys/kernel/debug/block/sdz/hctx23 /sys/kernel/debug/block/sdz/hctx30    
/sys/kernel/debug/block/sdz/hctx38
/sys/kernel/debug/block/sdz/hctx1 /sys/kernel/debug/block/sdz/hctx17 
/sys/kernel/debug/block/sdz/hctx24 /sys/kernel/debug/block/sdz/hctx31    
/sys/kernel/debug/block/sdz/hctx39
/sys/kernel/debug/block/sdz/hctx10 /sys/kernel/debug/block/sdz/hctx18 
/sys/kernel/debug/block/sdz/hctx25 /sys/kernel/debug/block/sdz/hctx32    
/sys/kernel/debug/block/sdz/hctx4
/sys/kernel/debug/block/sdz/hctx11 /sys/kernel/debug/block/sdz/hctx19 
/sys/kernel/debug/block/sdz/hctx26 /sys/kernel/debug/block/sdz/hctx33    
/sys/kernel/debug/block/sdz/hctx5
/sys/kernel/debug/block/sdz/hctx12 /sys/kernel/debug/block/sdz/hctx2    
/sys/kernel/debug/block/sdz/hctx27 /sys/kernel/debug/block/sdz/hctx34    
/sys/kernel/debug/block/sdz/hctx6
/sys/kernel/debug/block/sdz/hctx13 /sys/kernel/debug/block/sdz/hctx20 
/sys/kernel/debug/block/sdz/hctx28 /sys/kernel/debug/block/sdz/hctx35    
/sys/kernel/debug/block/sdz/hctx7
/sys/kernel/debug/block/sdz/hctx14 /sys/kernel/debug/block/sdz/hctx21 
/sys/kernel/debug/block/sdz/hctx29 /sys/kernel/debug/block/sdz/hctx36    
/sys/kernel/debug/block/sdz/hctx8
/sys/kernel/debug/block/sdz/hctx15 /sys/kernel/debug/block/sdz/hctx22 
/sys/kernel/debug/block/sdz/hctx3 /sys/kernel/debug/block/sdz/hctx37    
/sys/kernel/debug/block/sdz/hctx9
root@deadbird:~# ls -d /sys/kernel/debug/block/sdz/hc*|wc
      40      40    1390
root@deadbird:~# nproc
40

quoted

Please ask, if you need more data.

quoted

+ lsscsi
[0:0:0:0]    disk    ATA      ST500NM0011      PA09  /dev/sda
[0:0:32:0]   enclosu DP       BP13G+           2.23  -
[12:0:0:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdb
[12:0:1:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdc
[12:0:2:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdd
[12:0:3:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sde
[12:0:4:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdf
[12:0:5:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdg
[12:0:6:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdh
[12:0:7:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdi
[12:0:8:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdj
[12:0:9:0]   disk    SEAGATE  ST8000NM001A     E002  /dev/sdk
[12:0:10:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdl
[12:0:11:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdm
[12:0:12:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdn
[12:0:13:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdo
[12:0:14:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdp
[12:0:15:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdq
[12:0:16:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdr
[12:0:17:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sds
[12:0:18:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdt
[12:0:19:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdu
[12:0:20:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdv
[12:0:21:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdw
[12:0:22:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdx
[12:0:23:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdy
[12:0:24:0]  disk    SEAGATE  ST8000NM001A     E001  /dev/sdz
[12:0:25:0]  disk    SEAGATE  ST8000NM001A     E001  /dev/sdaa
[12:0:26:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdab
[12:0:27:0]  disk    SEAGATE  ST8000NM001A     E002  /dev/sdac
[12:0:28:0]  disk    SEAGATE  ST8000NM001A     E001  /dev/sdad
[12:0:29:0]  disk    SEAGATE  ST8000NM001A     E001  /dev/sdae
[12:0:30:0]  disk    SEAGATE  ST8000NM001A     E001  /dev/sdaf
[12:0:31:0]  disk    SEAGATE  ST8000NM001A     E001  /dev/sdag
[12:0:32:0]  enclosu AIC 12G  3U16SAS3swap     0c01  -
[12:0:33:0]  enclosu AIC 12G  3U16SAS3swap     0c01  -
[12:0:34:0]  enclosu Adaptec  Smart Adapter    3.21  -
[12:2:0:0]   storage Adaptec  1100-8e          3.21  -
+ for i in 12:2:0:0 12:0:34:0 12:0:33:0 12:0:31:0

I figure sdev queue depth is 64 for all disks, like /dev/sdag, below.

Yes, I send an example (one of two enclosures, 1 of 32 disks) but 
verified, that they are the same.

Confirmed my suspicions - it looks like the host is sent more commands 
than it can handle. We would need many disks to see this issue though, 
which you have.

So for stable kernels, 6eb045e092ef is not in 5.4 . Next is 5.10, and I 
suppose it could be simply fixed by setting .host_tagset in scsi host 
template there.

Thanks,
John