Messages in this thread |  | | Subject | Memory upgrade: not faster / nfs | From | Christoph Trautwein <> | Date | Fri, 25 Oct 1996 18:26:10 +0200 |
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Problem: ! NFS is a filesystem. Filesystems are not cached. ! The only thing that's cached in UN*X are block ! devices. This is the wrong place to cache.
My fastest CPU is a Pentium 100 on a diskless client. I thought that I get only 5% cpu usage because I am swapping over NFS. I bought another 32MB but the CPU usage did not increase :-( The Ethernet LED is still busy all the time. I tracked the problem down to the following problem:
! NFS is a filesystem. Filesystems are not cached. ! The only thing that's cached in UN*X are block ! devices.
Because of this configuration the caching is done in the server, not on the client =:-O Transmitting data over the network is some magnitudes slower than reading it from the buffers. Compiling is a very I/O intensive task (all the include files, the compiler, the .I .S .o files). For this it doesn't matter how much memory I have on my client. I can't get more than 5% CPU usage when compiling.
Questions: Is it correct how I see these things? Why are filesystems not buffered? Is there a nfs implementation that does buffering?
Christoph Trautwein email trautw@fzi.de click <A HREF="http://www.fzi.de/sim/people/trautw/index.html">here </A> FZI Forschungszentrum Informatik phone +49-721-9654-414 FZI,Haid-und-Neu-Str. 10-14, 76131 Karlsruhe, Germany fax +49-721-9654-474 X400: C=de; A=d400-gw; P=fzi; S=trautw * PLEASE USE PGP TO ENCRYPT EMAILS! Please use MIME formatted EMails. *
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