Date: Wed, 15 Dec 1999 14:22:03 -0500 (EST) From: Andrew Gallatin <gallatin@cs.duke.edu> To: Matthew Dillon <dillon@apollo.backplane.com> Cc: freebsd-current@freebsd.org Subject: Re: Serious server-side NFS problem Message-ID: <14423.59494.219984.475675@grasshopper.cs.duke.edu> In-Reply-To: <199912151912.LAA40369@apollo.backplane.com> References: <14423.46117.353932.473968@grasshopper.cs.duke.edu> <199912151912.LAA40369@apollo.backplane.com>
next in thread | previous in thread | raw e-mail | index | archive | help
Matthew Dillon writes: > > :Also, while read performance has improved by 44%, write performance > :has degraded by between 50 - 70% (FreeBSD clients)! Here are some > :quick benchmarks. Note that the file size of 512MB is larger than > :memory on both the server and client. Also note that the disk array > :on the server will read at 50MB/sec and write at 40MB/sec, so we are > :not disk bound ;-) > : > :- UDP NFS write performance from a FreeBSD client: > : > :July's kernel: > :% dd if=/dev/zero of=zot bs=1024k count=512 > :512+0 records in > :512+0 records out > :536870912 bytes transferred in 52.780773 secs (10171714 bytes/sec) > : > :Today's kernel:: > :% dd if=/dev/zero of=zot bs=1024k count=512 > :512+0 records in > :512+0 records out > :536870912 bytes transferred in 141.593458 secs (3791636 bytes/sec) > > Question on these: Is it the client you are running the old and new > kernels on or the server? Also, make sure you are running the same > number of nfsiod's on each (and also try running a different number > of nfsiod's). > > At the moment I am assuming you ran these tests with the client running > the old and new kernel. I have some ideas there in regards to inefficient > context switching when the nfsiod's are saturated that I am testing. > > -Matt Sorry I wasn't clear. The variable was the server's kernel version. The client's kernel remained constant. It was from sources built late week. When you are measuring server write performance, are you looking at the numbers from the client's perspective, or are you looking at the numbers from the point of view of the server's disks. I ask because if I watch the server via systat, I see a steady 10-11MB/sec hitting the disk. However, if I time the process, or look at the output from dd, I see the poor (< 4MB/sec) numbers I reported. Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?14423.59494.219984.475675>