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HNAS NFS mount in virtual guest *slow*

Question asked by Stefan Schwiedel on Feb 16, 2015
Latest reply on Apr 24, 2015 by Michael Ratner



we have a strange behavior at customer site with an HNAS mount within a VM guest.


There is the following config:


ESX Network1 VM Network 2x10G

ESX Network2 vmkernel traffic 2x10G


server1 on Network1 with FS1 mounted on /mount1


There is also another server2 with FS2 mounted directly on ESX for VM virtual disks.


dd on virtual disk ~450 MB / sec

dd on manual mounted /mount1 ~45kb with iowait 75%


I created some test shares on server 1 and fs1 and mounted them around several VMs with the same result.

Then I created a new FS on server2 and mounted this share over the second interface on the VM (using Network2) and got 180 MB/sec


There is absolutely nothing in the logs and not really much load on the HNAS or on the ESX.


Now the funny thing..... An rsync between mount1 and mount2 (on server2) copies ~3GB / 5min


No Bossocks no load, no nothing on the HNAS. I see I/Ops on the Filesystem 1 around 150


I`m pretty sure that the configuration of the MTU size is inconsistent in the network but this shouldn`t cause such a big issue - which happend suddenly.


I`m getting crazy....Does anyone have an idea?