Hi vmware technical and experts.
I just got the issue with VSAN performance going down when make vMotion operation.
My currently VSAN cluster setting is
-2 servers with 8x1TB HHD (RAID5) with 120GB SSD as cache each.
-internet 1000M network
-vSphere 6.5
when i operate the vMotion for a big size VM (over 3TB) from one server to another server base the vSAN,
there is a error shows below:
- database:VSAN health alarm 'congestion'
- after that i went to 'datacenter -- cluster -- monitoring -- Vsan -- health Tab'
- there are shows that 'Failed Physical Disk '
- Congestion -- Disk with issue -- congestion info 192(SSD)
And then i checked the VSAN performance status:
datacenter -- cluster -- monitoring -- VSAN-Backend -- current graph shows that Throughout just likely 15.02MB/s.
As my acknowledged that this speed is not full to the network bottleneck because the network bottleneck should be main port in this cluster which is top 124MB/s.
- Internet speed has been passed test and can be full to top.
- HHD speed has been passed test and can be top to 500-600mb/s.( can be ignored)
But performance monitoring shows the volume (15.02MB/s) is very low than the bottleneck (124MB/s).
I guess is it because my hard drive cache (ssd) is too small? Or for what other reasons, please point out and give some relevant documentation.
Thanks