Thank you Subhajit for your answer!
I also see this issue when I read the release note for new firmware 'VL270P004' (we are still using the previous one) as I was looking a potential fix.
Unfortunately, I reset all statistics (all topics) last week-end but the issue is still there. Live statistics using CLI does not show the Queue Depth (I only see it using SMU).
As you also observed such hight number (on my side it is about 8000 Million not 8000 [I check using the CLI] but I assume you just have a look on the scale [you should have a (M) [for Million] in the graph title]), I am not alone with this issue.
For now, you do not have performance issue as the number of IOs is very low (an average of 25 IOs per disk). It is just to verify MSA is working fine and having such number does not satisfy the customer (if this number is wrong what about other indicators).
I would prefer to not have this metric reported by SMU otherwise custuler raises a lot of questions (for instance disk errors are reported but without real disk issue; another mystery).
Thank again.
Regards