Date: Wed, 09 May 2018 04:25:36 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 228087] F_SETLK randomly fails on NFS4 in threaded operation in MySQL Message-ID: <bug-228087-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D228087 Bug ID: 228087 Summary: F_SETLK randomly fails on NFS4 in threaded operation in MySQL Product: Base System Version: 11.1-STABLE Hardware: Any OS: Any Status: New Severity: Affects Many People Priority: --- Component: kern Assignee: bugs@FreeBSD.org Reporter: barry.boes@acciodata.com Tried in 10.4, 11.1-RELEASE, 11.1-STABLE, and 11.2-PRERELEASE client and server. Currently client and server are 11.2-PRERELEASE. Ktrace shows the following : 66181 mysqld CALL close(0x30) 66181 mysqld RET openat 48/0x30 66181 mysqld CALL fcntl(0x30,F_SETLK,0x7fffdd3e5cc0) 66181 mysqld RET close 0 66181 mysqld RET fcntl -1 errno 13 Permission denied Examining a full trace, the files being locked are never locked twice by My= SQL or locked by another process. The file closed in the first line is a diffe= rent file than that opened in the second line. MySQL does this same operation = tens or hundreds of thousands of times successfully then fails on one. From all= of the trace data that I've been able to gather, the FCNTL works 100% of the t= ime IF the close returns before another thread calls open and F_SETLK and fails 100% of the time that the SETLK completes before the close returns in anoth= er thread. Observation affects the results. Failure occurs tens to hundreds of ti= mes more rapidly when not tracing the process. The higher the network latency, the more likely it is to happen. With a latency of 200uS, it happens in seconds on a loaded server. With a latency= of 100us, it happens in tens of seconds. With a latency of 20uS it happens rarely, and below 15uS I have yet to see this failure. No kernel messages are logged. I have duplicated the problem on a variety = of hardware, from 28 core Supermicro motherboards with ECC memory and E5-2XXX = V4's to laptops with i3's, 5's, or 7's. The filesystem setup is as follows : server : ZFS on 11.2-PRERELEASE configured for very low latency (optimized = SSDs and persistent write caches or sync=3Ddisabled). The filesystem is either a base ZFS filesystem or a clone of a snapshot (for easy testing, it happens on either). The client mounts the server system via NFS4 and also runs 11-2-PRERELEASE.= =20 Tested with 100Mb, gigabit, 50 gigabit, and 100Gigabit NICs. --=20 You are receiving this mail because: You are the assignee for the bug.=
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