> > I have seen the GETATTR return MAXREAD and MAXWRITE attribute values > set to 1MB during testing with Wireshark. My educated guess is that > this corresponds to RPCSVC_MAXPAYLOAD defined in linux/nfsd/const.h. > Would anyone agree with this? > > That's an upper limit and a server without a lot of memory may default > to something smaller. The GETATTR shows that it isn't, though. Memory shouldn't be a limit. I have the system isolated for testing - the server has ~126GB memory and the client has ~94GB. > > > If you haven't already I'd first recommend measuring your NFS read > > > and write throughput and comparing it to what you can get from the > > > network and the server's disk. No point tuning something if it > > > turns out it's already working. > > > > I have measured sequential writes using dd with 4k block size. > > What's your dd commandline? dd if=/dev/zero of=[nfs_dir]/foo bs=4096 count=1310720 Should result in a 5 GB file. > > The NFS > > share maps to a large SSD drive on the server. My understanding is > > that we have jumbo frames enabled (i.e. MTU 8k). The share is mounted > > with rsize/wsize of 32k. We're seeing write speeds of 200 MB/sec > > (mega-bytes). We have 10 GigE connections between the server and > > client with a single switch + multipathing from the client. > > So both network and disk should be able to do more than that, but it > would still be worth testing both (with e.g. tcpperf and dd) just to > make sure there's nothing wrong with either. > > > I will admit I have a weak networking background, but it seems like > we could achieve speeds much greater than 200 MB/sec, considering the > pipes are very wide and the MTU is large. Again, I'm concerned there is > a buffer somewhere in the Kernel that is flushing prematurely (32k, > instead of wsize). > > > > If there is detailed documentation online that I have overlooked, I > would much appreciate a pointer in that direction! > > Also, what kernel versions are you on? RH6.3, 2.6.32-279.el6.x86_64 -Jason -- 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
