I'm trying to time file transfer times to a RPi-3B+ serving over various protocols, and I ran into an odd problem. I'm not sure where to start looking to fix it, and I'm hoping someone can suggest a starting point.
Source computer is a Mac Mini running High Sierra. Target is a RPi-3B+ 4.14.79-v7+ #1159. Router is a Linksys E3000, Firmware Version: 1.0.06. All OSes/firmware up to date as of the last few days. All connections via GB Ethernet. NFS service on the RPi has as /etc/exports:
I've rebooted the RPi a couple of times to make sure I had a cleanly-started system.
I started testing by copying 10**6 1K blocks of random data from source to target. SMB worked fine. Tried the same command with the target mounted via NFS, and it hung the target RPi. Tinkered a bit and found that small transfers work fine, but after about 5MB of transfers, it hangs. Sequence demonstrating logged below.
At the time the transfer hangs, a connection on another SSH connection also hangs -- will not respond to any keystrokes, and any attempt to open another SSH connection in a new terminal window hangs as well ("host is down").
This isn't critical ... I'm just trying to figure out if I can reliably use NFS for transfers of arbitrary size to the Pi. But this particular constraint must be of my own creation -- didn't find anyone else reporting this problem. So I wonder if there's an obvious mistake in my setup.
Any suggestion on where to look?
mount -t nfs -o rw pi-1:/home/hdtodd/nfs p
bash-3.2# time dd if=/dev/random of=p/null_data bs=1024 count=10
10+0 records in
10+0 records out
10240 bytes transferred in 0.000465 secs (22014184 bytes/sec)
bash-3.2# time dd if=/dev/random of=p/null_data bs=1024 count=100
100+0 records in
100+0 records out
102400 bytes transferred in 0.005630 secs (18188224 bytes/sec)
bash-3.2# time dd if=/dev/random of=p/null_data bs=1024 count=1000
1000+0 records in
1000+0 records out
1024000 bytes transferred in 0.294398 secs (3478284 bytes/sec)
bash-3.2# time dd if=/dev/random of=p/null_data bs=1024 count=1000000
dd: p/null_data: Input/output error
5378+0 records in
5377+0 records out
5506048 bytes transferred in 43.478419 secs (126639 bytes/sec)