VMware: set­ting the stor­age device queue depth (HDS fibre chan­nel disks)

Prob­lem

In 2017 we replaced an IBM stor­age sys­dem with an Hitachi Van­tara stor­age sys­tem (actu­al­ly, we replaced the com­plete SAN infra­struc­ture). We han­dled it by attach­ing both stor­age sys­tems to VMware (v5.5) and migrat­ing the data­s­tores. A rec­om­men­da­tion from Hitachi Van­tara was to set the queue depth for fibre chan­nel disks to 64.

Solu­tion

Here is a lit­tle script which does that. Due to issues as described in a pre­vi­ous post which caused HA/FA (High Avail­abil­i­ty / Fault Tol­er­ance) reac­tions in VMware to trig­ger, we played it safe and added a lit­tle sleep after each change. The script also checks of the queue depth is already set to the desired val­ue and does noth­ing in this case. It’s small enough to just copy&paste it direct­ly into a shell on the host.

SLEEPTIME=210 # 3.5 minutes  !!!! only if all RDMs on the host are reserved!!!
TARGET_DEPTH=64
for LDEV in $(esxcli storage core device list | grep "HITACHI Fibre Channel Disk" | awk '{gsub(".*\\(",""); gsub("\\).*",""); print}'); do
  echo $LDEV
  DEPTH="$(esxcli storage core device list -d $LDEV | awk '/outstanding/ {print $8}')"
  if [ "$DEPTH" -ne $TARGET_DEPTH ]; then
    echo "   setting queue depth $TARGET_DEPTH"
    esxcli storage core device set -d $LDEV -O $TARGET_DEPTH
    echo "   sleeping $SLEEPTIME"
    sleep $SLEEPTIME
  else
    echo "    queue depth OK"
  fi
done
Send to Kin­dle

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.