I manage a
vagrant setup for our developers running OSX to manage VirtualBox systems for development.
In order to support
inotify inside the linux machine, we eschew the usual method of sharing directories with VirtualBox: instead, the Virtualbox machine exposes an NFS share, which is mounted in OSX.
Git (and related tools like sourcetree) are run in OSX, on the shared directory. The performance of this is extremely poor: it often takes up to 5 seconds just to run
git status. Cloning a small repository into the mounted NFS drive can take a couple of minutes (5-10 seconds on a local drive).
Obviously NFS performance will be worse than writing straight to a local SSD, but the NFS is just running over a virtual private network interface with Virtualbox.
I ran a couple of benchmarks. The first:
dd if=/dev/zero of=test bs=16 count=16384
Each result is based on 100 samples.
# local drive Min. 1st Qu. Median Mean 3rd Qu. Max. 0.990 1.000 1.020 1.021 1.030 1.130 # on the shared NFS drive Min. 1st Qu. Median Mean 3rd Qu. Max. 6.000 6.278 6.390 6.482 6.570 7.630 # inside the VirtualBox instance Min. 1st Qu. Median Mean 3rd Qu. Max. 0.3600 0.4800 0.5150 0.5552 0.5400 1.4500
The second benchmark:
ioping -c 500
local avg: 6 microseconds local IOPS: 65.5 k NFS Latency avg: 703 microseconds NFS OPS: 1.4 k
Clearly some latency is inevitable, but this is bad enough that it makes some simple tasks quite painful.
The owner of the volume is running Ubuntu 12.10 (Quantal), with default settings. The system mounting the volume is running OSX Mavericks.
At the moment the main nfsd connection is running over UDP, which seems ideal over a virtual connection. I'm not sure whether
lockd are running over TCP and UDP.
I tried mounting with the
async flag, and with
rwsize boosted, and it made little difference.
What opportunities are there for seriously improving the performance of NFS in this environment?