How to check the queue depth (qdepth) value for external stroage on PDA

Answer

The Linux kernel version 2.6 and later uses sysfs. One can use sysfs to list all scsi devices and hosts attached to the server powered by Linux kernel 2.6 and later. The lsscsi command is handy tool to get all sort of information in sysfs (linux kernel series 2.6 and later) to list scsi devices (or hosts) currently attached to the system.

User can use an option -l to output additional information for each SCSI device (host) including the queue depth value. This option can be used multiple times for more output in which case the shorter form is more convenient (e.g. ’-lll’).

# lsscsi -l
[5:0:0:0]    disk    SCST_FIO lvol0             200  /dev/sdb
  state=running queue_depth=30 scsi_level=6 type=0 device_blocked=0 timeout=60

#lscsi -lll
[5:0:0:0]    disk    SCST_FIO lvol0             200  /dev/sdb
  device_blocked=0
  iocounterbits=32
  iodone_cnt=0x37ec
  ioerr_cnt=0x2
  iorequest_cnt=0x37ec
  queue_depth=30
  queue_type=none
  scsi_level=6
  state=running
  timeout=60
  type=0