updating via svn and usb2 thumbdrives

Hi,

When updating, particularly when downloading the src or ports tree for
the first time, even though I've taken all approaches possible to speed
up access to attached usb2 drives, I'll get these errors which will
cause the update to bail:

A    ports/www/py-django-otp
svn: E120106: ra_serf: The server sent a truncated HTTP response body.

where it'll remain until I restart it but sometimes it'll crash so badly
svn will demand svn cleanup on the dir I'm downloading to, like this:

A    ports/www/elgg/files
svn: E120106: ra_serf: The server sent a truncated HTTP response body.
# svnlite co https://svn0.eu.FreeBSD.org/ports/head /ext/ports
svn: E155004: Run 'svn cleanup' to remove locks (type 'svn help cleanup'
for details)
svn: E155004: Working copy '/ext/ports' locked.
svn: E155004: '/ext/ports' is already locked.

So I do this:

# svnlite cleanup /ext/ports

...and I can start svnlite again.

I'm sure this has to do with the thumbdrive 'catching up' with writing.
So my question is this: Is there some switch in svnlite or some tool or
parameter I can give to the process that will either buffer or limit the
demands made of the device? It's UFS2 mounted with -o async[might be
redundant],rw and has soft-updates but no journalling.

My connection speed is 23Mbit so I'm thinking that on usb2 this might be
approaching its random write speed but i'm unsure. What's the best way
to permanently fix this?

thanks,
-- 
J.