Hello,
I have lot of “VM Write latency” on a new vSAN infrastructure :
- Version 7.0
- Full Flash
- 7 hosts (Dell poweredge 740xd)
- de-duplication and compression are off
Actually, the no traffic on the infrastructure.
I use this command to generate benchmark :
[root@a ]$ dd if=/dev/zero of=/test_io/test-24Go bs=1G count=24 iflag=fullblock oflag=direct;
24+0 records in
24+0 records out
25769803776 bytes (26 GB, 24 GiB) copied, 45.7959 s, 563 MB/s
The VM where I launched the command is configured like this :
- Centos 8
- 2 CPU
- 2 Go RAM
- NVME Controller
- RAID 1
The graphs :
On the backend :
Host network :
If I configure the VM in RAID 0, I have no issue and it’s more fast :
[root@a ]$ dd if=/dev/zero of=/test_io/test-24Go bs=1G count=45 iflag=fullblock oflag=direct
45+0 records in
45+0 records out
48318382080 bytes (48 GB, 45 GiB) copied, 63.9457 s, 756 MB/s
Any idea ?