I recently re-built my NAS box and now I've run into a strange problem that seems to be specific to Mint-10. First some background...
My old NAS ran the 32-bit version of FreeNAS 0.7.2 and was based on an old Intel Pentium-3 with a generic Gigabit NIC. I used that NAS extensively for over a year without any trouble. I regularly moved large amounts of data back and forth with no problems other than it being a bit slow (about the same speed as a USB hard drive).
I wanted more performance and room so I upgraded the motherboard (CPU/RAM) and added a couple of 2TB HDDs. The new NAS box has an Intel D525MW dual-core Atom board with a Realtek 8111E Gigabit NIC, 4GB of RAM and is running FreeNAS 0.7.2 embedded (same software, only the 64-bit version).
I'm using the NAS as an NFS share on a CAT-6 wired Gigabit network.
When I try to copy a large file to the NAS my system locks up hard. And I mean HARD, as in I have to use REISUB! Note that it's not the NAS locking up, it's the computer sending the file to the NAS. The NAS is fine, and all other computers on my network can still access it.
But it only happens when I send a large file (2GB or so). I can send loads of small files with no trouble. I can grab a folder with 10GB(+) of photos or MP3 files and it will copy fine. But try and drop a single 2GB video file onto the NAS and BAM!
What happens is, somewhere between 25% and 75% of the way into the copy operation it just stops. The progress indicator stops and all NAS activity ceases. Network traffic and CPU usage on the NAS drops to zero. Note again that the NAS is fine at this point. On my end, however, the system monitor shows heavy CPU usage, but minimal network activity.
What's odd is the process monitor shows NO CPU activity. All running processes are "sleeping" with zero CPU usage, but the resources graph shows CPU1=100% & CPU2=35-50%.
So, question #1, how can I have so much CPU activity with no running processes using it?
If I try to abort the copy operation by hitting the stop button on the progress indicator it turns gray and it won't close or abort. System is still usable but slow. If I try to reboot I get an error telling me there is a file copy operation in progress, and Nautilus won't quit. If I try and kill Nautilus it goes Zombie and both CPUs get pegged at 100%. Shortly after that everything freezes. Can't use the mouse, etc. I have to use Alt+Sysrq REISUB.
And it ONLY happens with Mint-10.
Mint-9 is fine... Mint-11 is fine... Windows is fine...
Tried the Mint-10 install on my test partition, which is still pretty virgin (only has the original level 1-3 updates) and it still locks up. Tried to do a full dist-upgrade on my main install (new kernel and all) and, same problem. Replaced Mint-10 with Mint-11 on my test partition (so same computer, different Mint) and, no problem, it works.
Tried uninstalling nfs-common and using Samba and it works, but it's very, very slow (about 1/4th the speed of nfs). So it seems to be a problem with nfs. Purged nfs-common and portmap and did an apt-get clean & autoclean, then re-installed, but the problem persists.
This one has got me completely stumped. Don't even know where to start.

Anyone got any ideas?