On 2011-06-30 17:24, Trond Myklebust wrote: > On Thu, 2011-06-30 at 09:36 -0400, Andy Adamson wrote: >> On Jun 29, 2011, at 10:32 PM, quanli gui wrote: >> >>> When I use the iperf tools for one client to 4 ds, the network >>> throughput is 890MB/S. It reflect that it is indeed 10GE non-blocking. >>> >>> a. about block size, I use bs=1M when I use dd >>> b. we indeed use the tcp (doesn't the nfsv4 use the tcp defaultly?) >>> c. the jumbo frames is what? how set mtu automatically? >>> >>> Brian, do you have some more tips? >> >> 1) Set the mtu on both the client and the server 10G interface. Sometimes 9000 is too high. My setup uses 8000. >> To set MTU on interface eth0. >> >> % ifconfig eth0 mtu 9000 >> >> iperf will report the MTU of the full path between client and server - use it to verify the MTU of the connection. >> >> 2) Increase the # of rpc_slots on the client. >> % echo 128 > /proc/sys/sunrpc/tcp_slot_table_entries >> >> 3) Increase the # of server threads >> >> % echo 128 > /proc/fs/nfsd/threads >> % service nfs restart >> >> 4) Ensure the TCP buffers on both the client and the server are large enough for the TCP window. >> Calculate the required buffer size by pinging the server from the client with the MTU packet size and multiply the round trip time by the interface capacity >> >> % ping -s 9000 server - say 108 ms average >> >> 10Gbits/sec = 1,250,000,000 Bytes/sec * .108 sec = 135,000,000 bytes >> >> Use this number to set the following: >> sysctl -w net.core.rmem_max = 135000000 >> sysctl -w net.core.wmem_max 135000000 >> sysctl -w "net.ipv4.tcp_rmem <first number unchaged> <second unchanged> 135000000" >> sysctl net.ipv4.tcp_wmem <first number unchaged> <second unchanged> 135000000" >> >> 5) mount with rsize=131072,wsize=131072 > > 6) Note that NFS always guarantees that the file is _on_disk_ after > close(), so if you are using 'dd' to test, then you should be using the > 'conv=fsync' flag (i.e 'dd if=/dev/zero of=test count=20k conv=fsync') > in order to obtain a fair comparison between the NFS and local disk > performance. Otherwise, you are comparing NFS and local _pagecache_ > performance. FWIW, modern versions of gnu dd (not sure exactly which version changed that) calculate and report throughput after close()ing the output file. Benny > > Trond -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
