On Jul 28, 2018 19:30, Wesley Stewart <wstewart3@gmail.com> wrote:

I have added the "async" option to the "additional mount options" section.

Transferring from my raided SSD mirrors is QUITE fast now.

However, this might be confusing, but if I read/write to the nfs share at the same time performance plummits.  

So if I grab something from the SMB share over 10gb network and write this to my VM being hosted on the NFS share.  Bad performance.

Or If I copy and paste ISO from the VM to itself, horrible performance.

If I grab a file from a VM on my raised SSD storage and copy it to my VM on the NFS Share, it has great performance (400+ MB/s)

Not quite sure what's going on!  However if I grab something from the 1gbps network everything seems okay.  Or if I change the NFS Mount to the 1 gbps everything is okay. 

Any ideas?

Let's start with expectations, shall we? 10Gb ~ 1 GB/s. So you read a file over SMB and write that to a VM hosted on NFS, so remote to remote. The absolute max for that transfer would be ~ 500 MB/s. What do you get?

/K

On Sat, Jul 28, 2018 at 3:02 AM Karli Sjöberg <karli@inparadise.se> wrote:

On Jul 28, 2018 01:01, Wesley Stewart <wstewart3@gmail.com> wrote:

I currently have a NFS server with decent speeds.  I get about 200MB/s write and 400+ MB/s read.  

My single node oVirt host has a mirrored SSD store for my Windows 10 VM, and I have about 3-5 VMs running on the NFS data store.

However, VM/s on the NFS datastore are SLOW.  They can write to their own disk around 10-50 MB/s.  However a VM on the mirrored SSD drives can get 150-250 MB/s transfer speed from the same NFS storage (Through NFS mounts).

Does anyone have any suggestions on what I could try to speed up the NFS storage for the VMs?  My single node ovirt box has a 1ft Cat6 crossover cable plugged directly into my NFS servers 10GB port.

Thanks!

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It may be because of how oVirt mounts them, much more carefully, than Linux does by default. If I am not mistaken, oVirt mounts the NFS shares with 'sync', whereas a standard 'mount' with no options gets you 'async'. The difference in performance is huge, but for a reason; it's unsafe in case of a power failure. That may explain things.

/K