Slow SSHFS transfer speeds under OSX

If you’ve noticed that SSHFS transfers are much slower (several times slower) than SCP on macOS, you're not alone. This issue seems to be tied to how macFUSE and SSHFS interact, particularly around I/O block size. A detailed discussion about the root cause of this problem can be found in a GitHub issue thread.

The good news is that in the tread it is also proposed a fix: increase the I/O block size. By setting it to 1MB (-o iosize=1048576), I was able to significantly speed up transfers with just a small 10% overhead.

I applied this change by adding it to my ~/.zshrc (or ~/.bashrc):

     alias sshfs='sshfs -o iosize=1048576'

It's a quick win if you rely on SSHFS for remote file systems!