Date: Wed, 2 Feb 2000 10:59:34 -0800 (PST) From: Matthew Dillon <dillon@apollo.backplane.com> To: "Ronald G. Minnich" <rminnich@lanl.gov> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Re/Fwd: freebsd specific search Message-ID: <200002021859.KAA00937@apollo.backplane.com> References: <Pine.LNX.4.20.0002021041230.804-100000@mini.acl.lanl.gov>
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:On Wed, 2 Feb 2000, Michael Bacarella wrote:
:> Granted, a lot of Linux distributions are totally unsuited for a server
:> environment. Compared to that, I could understand why the
:> server-orientedness of FreeBSD is attractive, but I certainly couldn't put
:> up a reasonable arguement for either side in Slackware Linux vs. FreeBSD.
:
:Linux is definitely a less reliable system for clustering than freebsd.
:I've got 5 years of running them both at Sarnoff to back me up. Maybe I
:was doing something wrong, but I'm seeing similar problems here at the ACL
:on Linux.
:
:We ran into four classes of problems that linux had that freebsd did not.
:These problems are still not fixed as of 2.2.x or 2.3.x.
:
:1) network stack. heavy use of udp can result in a hung kernel. Trivial
: TCP servers that need to take lots of connections cause trouble --
: clients start getting ECONNREFUSED after a while
:2) nfs. Hit nfs hard and random clients will hang. The dirty little
: secret of linux clusters is that 'everyone knows' that you don't run
: client nfs on linux cluster nodes if you want the cluster to stay up.
: This came out clearly at a cluster conference last spring (JCP4).
:3) vm system. There's still some strange problems in there.
:4) ext2. ext2 does not handle unplanned outages well. There is a
: reasonable chance that after a power fail you're going to have trouble
: if you have 100 nodes or more. You'll see 2 or 3 in need of help.
:
:freebsd was just more solid on our clusters. But note that linux isn't
:standing still -- it's just not as good as freebsd yet. I had one freebsd
:cluster that ran through 5 years of anything we could throw at it -- power
:fail, etc. It took disk death to finally halt one node and require me to
:hook up a keyboard to it to reload it.
:
:Our general experience was that NT fails a lot, esp. if you ask it to talk
:to a network or run a screensaver. Linux clusters run a long time, but
:power outages and other unplanned events will cause it trouble. Freebsd
:tolerates very high levels of abuse. The UFS guys really know their stuff.
:
:ron
Linux has made great strides in the performance area -- the are way ahead
of us on SMP issues, but they are definitely still behind in the
reliable department. They almost caught up when we were going through
our 3.0/3.1 fiasco but then fell behind again. I agree with your general
assessment (though I'm even more rabid about NT, which I consider
plain and simply to be a piece of crap).
It interesting to note that two years ago it was well known that running
NFSv3 under FreeBSD would destabilize it, so most people ran NFSv2.
Even NFSv2 2 years ago had problems. Linux is just reaching the point
now with NFSv2 where we were with NFSv3 two years ago. Thus in regards
to NFS, FreeBSD is about 2 years ahead of Linux. At this time both
NFSv2 and NFSv3 under FreeBSD are considered stable and reliable.
-Matt
Matthew Dillon
<dillon@backplane.com>
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