<p>NFS Large File writing causing "freezes"</p>
<p>I'm currently in the process of backing up a large number of DVD's (due to children destroying DVD's) to the computer. The process was 2 machines ripping directly to one of the machines hard drives, and a cluster of machines encoding from that machines hard drive (over NFS) to a NAS (also over NFS).</p>
<p>As the hard drive I was ripping to was small, I changed to having the ripped iso's on another NAS's hard drive, over NFS. So I had 2 machines ripping from local DVD drives directly to a NFS drive. On one of the machines I noticed it would every now and then "freeze" (become unresponsive but things like the netspeed applet would continue just fine) for a little while, always while the netspeed monitor read high speeds, until the speeds slowed down and then it would start responding again. For this reason I changed to ripping to local hard drive, and then after the ripping process, transfer the file to the NFS drive. This was working ok, but on the machine that had been freezing, it made the problem worse. While ripping, everything was just fine, no freezes. When I tried to transfer the file, I would then get freezes for even longer than last time. The end result is that the file does transfer fine, it would appear that it attempts to send it over the network too fast for the NAS and in the process freezes up the computer. The load goes up, but the memory usage doesn't change.<br>
I've tried changing the wsize and rsize values. I've halved them from what the server auto negotiated and even that doesn't work. If I rsync or scp the files then I don't have any of the problems, but it does go a lot slower than NFS. (Even with the freezes).<br>
I've done some googling and reading of NFS network issues and tried to find what I can do to fix it. The computer and the NAS are both on a Gigabit switch which appears to be fine.<br>
Attempting to transfer to the other NAS also exhibits the same issue.</p>
<p>Any ideas to get this working welcomed. Reads from the NAS's work fine, reaching 20MB/s and averaging around 18MB/s from the slower NAS (max), and reaching 33MB/s and averaging 30MB/s from the faster NAS (korby, the main one I'm trying to write big files too). Korby is a QNAP TS-410, reading and writing to a 2TB WD drive (not in RAID). Max is a WD My Book World Edition 1TB WD drive also not in RAID.</p>
<p>Below is some of the "debug" info to try and help with working out the issue. ifconfig on the client doesn't show any errors. ifconfig on the server does show errors.</p>
<p># ifconfig (server)<br>
eth0 Link encap:Ethernet HWaddr 00:08:9B:BD:3E:8A <br>
inet addr:192.168.8.100 Bcast:192.168.8.255 Mask:255.255.255.0<br>
UP BROADCAST RUNNING ALLMULTI MULTICAST MTU:1500 Metric:1<br>
RX packets:134427956 errors:31444 dropped:31444 overruns:0 frame:0<br>
TX packets:69530742 errors:0 dropped:0 overruns:0 carrier:0<br>
collisions:0 txqueuelen:1000 <br>
RX bytes:1457307119 (1.3 GiB) TX bytes:3046433619 (2.8 GiB)<br>
Interrupt:15 </p>
<p>/proc/mounts<br>
max:/nfs/Media /mnt/DVD_Encode nfs rw,relatime,vers=3,rsize=16384,wsize=16384,namlen=255,soft,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.8.200,mountvers=3,mountproto=tcp,addr=192.168.8.200 0 0<br>
korby:/share/HDD_DATA/DVD_rip /mnt/DVD_rip nfs rw,relatime,vers=3,rsize=32768,wsize=32768,namlen=255,soft,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=192.168.8.100,mountvers=3,mountport=48206,mountproto=udp,addr=192.168.8.100 0 0<br>
<br></p>
<p>$ nfsstat -o net<br>
Server packet stats:<br>
packets udp tcp tcpconn<br>
452217 3 452189 15 </p>
<p>Client packet stats:<br>
packets udp tcp tcpconn<br>
0 0 0 0 <br>
</p>