Date: Tue, 16 Jun 1998 23:36:28 +0800 From: Al Chen <hua@nease.net> To: freebsd-questions@FreeBSD.ORG Subject: Re: Is there any "race condition" in FFS? Message-ID: <3.0.32.19980616233605.0068f80c@mail.nease.net>
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Actually, we think our server's error is a very rare condition, because we have set up many FreeBSD servers ,and there was nothing wrong actually,and also,as we limit the numbers of qmail-smtpd process to 60,the system seems become stable, and only when the number of smtp connections is over 100,the problem will come out. And actually maybe it's just with qmail (which do many many file operation in mail queue). Our server is a compaq Server ,pentium Pro-200 CPU and 256M,and NCR SCSI card and seagate 4.3G UW HD. and as the load of the system is very low,so we want to bring up the number of the smtp connection, and then the error happen sometimes when there are over 100 smtp connections . Of course we believe that,this is a disk block realloc error and the error message is always "blkfree: freeing free block" which can be found in ffs_alloc.c,and the function is release a whole block which is totally free (and as there are no error of "freeing free frag",so we believe that there is nothing wrong in freeing some space which is not a total block). sometimes we really wants to comment the lines which make the panic error in that file and recompile the kernel :) And now we just limit the number of the SMTP connections and the system seems stable,and may be we will upgrade it to 3.0 later,but we are really want to find out the reason of the problem,as we really spend much time on it,but it's so hard to dig into the code ....... And we think maybe the dumping of the crash is not needed,because the problem must be happened sometime before the crash,and maybe the core couldn't help to find out the problem. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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