Date: Sat, 7 Feb 2009 15:40:05 GMT From: Martin Birgmeier <martin@email.aon.at> To: freebsd-fs@FreeBSD.org Subject: Re: kern/131360: [nfs] poor scaling behavior of the NFS server under load Message-ID: <200902071540.n17Fe5nN062750@freefall.freebsd.org>
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The following reply was made to PR kern/131360; it has been noted by GNATS. From: Martin Birgmeier <martin@email.aon.at> To: bug-followup@FreeBSD.org Cc: Subject: Re: kern/131360: [nfs] poor scaling behavior of the NFS server under load Date: Sat, 7 Feb 2009 16:31:21 +0100 (CET) I am now very sure that this is an interaction with pppoa, and it is also worse than I originally thought: it will even lead to failed NFS transactions for the client. Here is what I have: Machine A ('server', a mini home server) does the following: - connecting to the Internet using usermode ppp over pppoa over an Alcatel ADSL modem - NFS serving FreeBSD sources Machine B does the following: - Mounting the FreeBSD sources from A (using amd), under directory /vol/SRC/FreeBSD/HEAD/src - Compiling the FreeBSD sources: make -j4 buildworld, such that the corresponding obj is local (via amd again) Especially in the first phase of the buildworld (clean, depend, obj), there is a lot of simultaneous NFS traffic from B to A. As soon as a download is started at A (going via pppoa, of course), the load on A rises to very high values (> 20 not uncommon). This may lead to B aborting the compile, it just did that with "directory not found". Both machines are running 7.1.0. No such problem happended when both were running 6.3.0.
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