ESXi 6.0U3 slow disk performance

[adriankoooo]

Hi,

I have a HP Microserver g8 and ESXi 6.0U3. 

I am experiencing slow disk (WD RED WD30EFRX) performance in ESXi 6.0U3. Read performance is pretty normal, but writing performance is awful:

madrian@ubuntu:~$ sudo hdparm --direct -t -T /dev/sdc

/dev/sdc:
Timing O_DIRECT cached reads: 2836 MB in 2.00 seconds = 1421.50 MB/sec
Timing O_DIRECT disk reads: 442 MB in 3.01 seconds = 146.93 MB/sec
madrian@ubuntu:~$ cd^C
madrian@ubuntu:~$ cd /media/hdd/Downloads/
madrian@ubuntu:/media/hdd/Downloads$ dd if=/dev/zero of=test.file bs=64M count=16 oflag=dsync
16+0 records in
16+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 16.8884 s, 63.6 MB/s

Is there anything I can check to improve performance?

[pmichelli]

What array controller do you have in that box? It has been ages since I managed HPE. I do know if you reboot the server and press F8 or whatever the key is now when it initializes the SCSI controller, you can play with cache settings. I would start there.

Edit : I see you posted this from a VM. So many things to consider

1. What is the hardware type of the VM
2. What version of Ubuntu
3. Are you using multipathing drivers in Ubuntu?
4. What is the virtual storage controller ? LSI Logic SAS ? 
5. How many VMs are running off the same datastore?
6. How do other VMs perform?
7. What is the underlying storage type on the server? SAS ? SCSI ? SATA ? And what speeds are the drives / Array controller?

[compdigit44]

Is this a new issue? Are all VM's experiencing slow write performance?