core-dumping over NFS

Don Lewis truckman at FreeBSD.org
Mon Jan 12 14:29:55 PST 2004


On 12 Jan, Doug White wrote:
> On Mon, 12 Jan 2004, Don Lewis wrote:
> 
>> On 12 Jan, Mikhail Teterin wrote:
>>
>> > 	. 5.2-CURRENT (Dec 14) server, RedHat-9 client:
>> > 		core is created properly, but sometimes the server goes
>> > 		into a frenzy with the sys-component (bufdaemon) taking
>> > 		up the entire 100% of the CPU-time (P4 at 2GHz); it only
>> > 		writes @4Mb/s (~14% of the disk's bandwidth) and the
>> > 		only cure is to restart the /etc/rc.d/nfsd; trying to,
>> > 		for example, switch from X11 to a textual console, when
>> > 		this is happening reliably hangs the machine.
>>
>> I saw something similar a in the last month when running iozone on a
>> FreeBSD client with an nfs file system mounted from a FreeBSD server.  I
>> think this was in the 5.2-BETA timeframe.  The client typically ran out
>> of CPU first, but the server was not far behind.  This happened in the
>> tests with the larger file and/or block sizes.  Bufdaemon was typically
>> the big consumer of CPU.
> 
> Hm, I can attempt to reproduce this on 5.2-rel or -current. Can you
> provide the options used to iozone?

I think I used the defaults other than cranking up the max file size go
1GB to match the memory size on my server.  It took a long time to run
the full set of tests ...


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