commit d7ac4d913019345884c548dfd05f8bdffcee9d16 Author: rl1987 <rl1987@sdf.lonestar.org> Date: Fri Nov 14 23:07:35 2014 +0200 Adding section on OpenBSD to doc/TUNING --- changes/doc13702 | 4 ++++ doc/TUNING | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 64 insertions(+) diff --git a/changes/doc13702 b/changes/doc13702 new file mode 100644 index 0000000..917dca3 --- /dev/null +++ b/changes/doc13702 @@ -0,0 +1,4 @@ + o Documentation: + - Adding section on OpenBSD to our TUNING document. Thanks to + mmcc for writing the OpenBSD-specific tips. Resolves ticket + 13702. diff --git a/doc/TUNING b/doc/TUNING index a4bf386..90bd120 100644 --- a/doc/TUNING +++ b/doc/TUNING @@ -35,6 +35,66 @@ when it launches tor service (see launchd.plist(5) manpage). Also, kern.ipc.maxsockets is determined dynamically by the system and thus is read-only on OS X. +OpenBSD +------- + +For recent versions of OpenBSD (5.5 and 5.6, and probably older releases +as well), the maximum number of file descriptors that can be opened is +7030: + +http://unix.stackexchange.com/questions/104929/does-openbsd-have-a-limit-to-... + +The maximum number of file descriptors that an OpenBSD machine can have +open is stored in the sysctl variable kern.maxfiles. This value defaults +to 7030 - to verify this, run sysctl kern.maxfiles. + +To immediately change a running system's file descriptor limit to, for +example, 20,000 files, run sudo sysctl kern.maxfiles=20000. All sysctl +variables are reset upon reboot using defaults and /etc/sysctl.conf, so +to make your change permanent you must add the line kern.maxfiles=20000 +to /etc/sysctl.conf. + +One can also change a maximum number of allowed file descriptors for Tor +daemon alone by editing /etc/rc.d/tor and adding the following lines: + +tor:\ + :openfiles-max=8192:\ + :tc=daemon: + +However, there are stricter limits set on users. This is a security +feature intended to prevent one user from choking out others by opening +all possible file descriptors. + +The stricter limits are set in /etc/login.conf. This config file sets +resource access rules for user classes. You should be running +Tor as a non-privileged daemon user '_tor', which belongs to the 'daemon' +class. It will therefore be subject to the 'default' and 'daemon' rules. +There are two relevant rules: openfiles-cur and openfiles-max. The prior +is the initial limit upon login - the soft limit. The latter is the maximum +limit that can be set using 'ulimit -n' or setrlimit() without editing +/etc/login.conf and rebooting. This is known as the hard limit. + +Without editing /etc/login.conf, daemon-owned processes have +soft limit of 512 open files and a hard limit of 1024 open files. +Tor can increase the soft limit as needed, so you will therefore +eventually get warnings about running out of available file descriptors +once Tor reaches ~1024 open files. + +To increase the hard limit, add the following line to the daemon class +rules in /etc/login.conf: + +tor:\ + :openfiles-max=8192:\ + :tc=daemon: + +Upon restarting the machine, Tor will be able to open up to 6500 file +descriptors. + +Be aware that, by doing this, you are bypassing a security and stability +feature of the OS. If you are running your relay on a weak or old system, +watch your system load to ensure that it can handle this many open files. +Also, Tor may interfere with any other programs that open many files. + Disclaimer ----------