Date: Tue, 20 Jul 2004 05:37:11 -0600 From: Scott Long <scottl@samsco.org> To: jesk <jesk@killall.org> Cc: freebsd-current@freebsd.org Subject: Re: I/O or Threading Suffer Message-ID: <40FD03E7.8000300@samsco.org> In-Reply-To: <028601c46e46$38fc9560$45fea8c0@turbofresse> References: <028601c46e46$38fc9560$45fea8c0@turbofresse>
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jesk wrote: > hello, > > i got problems with mysql under freebsd 5.2.1 and CURRENT. > > i got these problems on two machines with different hardware, but both are > single cpu machines. > used scheduler is ULE. > > problem description: > under high i/o load the mysqld isnt responding any more. > i tested this with dd if=/dev/urandom of=testfile bs=128k on the hdd an was > not > able to become any ouput from simple select-statements within a long period > of time > (above minutes). > i dont know if this problem occurs from mysql and its threads or if the i/o > subsystem has > any problems to deal fast enough with two intensives read and write > processes and its > priorities. > > best regards, > christian > If you are dd'ing from /dev/random, then you are depleting the entropy pool. Anything else that tries to get random numbers is going to block in strange ways. Trying just dd'ing from /dev/zero and see if that makes a difference. Scott
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