Windows reportes about 500-600 MB/s over a 4GB file. However I believe I found the issue. My NFS backend is ZFS which is apparently notorious for horrible sync writes. https://forums.freenas.org/index.php?threads/sync-writes-or-why-is-my-esxi-n... I will try an iSCSI target and see how that goes. On Sat, Jul 28, 2018, 1:49 PM Karli Sjöberg <karli@inparadise.se> wrote:
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.
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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