diff options
Diffstat (limited to 'doc/TUNING')
| -rw-r--r-- | doc/TUNING | 86 |
1 files changed, 86 insertions, 0 deletions
diff --git a/doc/TUNING b/doc/TUNING new file mode 100644 index 0000000000..24552a38cb --- /dev/null +++ b/doc/TUNING @@ -0,0 +1,86 @@ +Most operating systems limit an amount of TCP sockets that can be used +simultaneously. It is possible for a busy Tor relay to run into these +limits, thus being unable to fully utilize the bandwidth resources it +has at its disposal. Following system-specific tips might be helpful +to alleviate the aforementioned problem. + +Linux +----- + +Use 'ulimit -n' to raise an allowed number of file descriptors to be +opened on your host at the same time. + +FreeBSD +------- + +Tune the followind sysctl(8) variables: + * kern.maxfiles - maximum allowed file descriptors (for entire system) + * kern.maxfilesperproc - maximum file descriptors one process is allowed + to use + * kern.ipc.maxsockets - overall maximum numbers of sockets for entire + system + * kern.ipc.somaxconn - size of listen queue for incoming TCP connections + for entire system + +See also: + * https://www.freebsd.org/doc/handbook/configtuning-kernel-limits.html + * https://wiki.freebsd.org/NetworkPerformanceTuning + +Mac OS X +-------- + +Since Mac OS X is BSD-based system, most of the above hold for OS X as well. +However, launchd(8) is known to modify kern.maxfiles and kern.maxfilesperproc +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 +------- + +Because OpenBSD is primarily focused on security and stability, it uses default +resource limits stricter than those of more popular Unix-like operating systems. + +OpenBSD stores a kernel-level file descriptor limit in the sysctl variable +kern.maxfiles. It defaults to 7,030. To change it to, for example, 16,000 while +the system is running, use the command 'sudo sysctl kern.maxfiles=16000'. +kern.maxfiles will reset to the default value upon system reboot unless you also +add 'kern.maxfiles=16000' to the file /etc/sysctl.conf. + +There are stricter resource limits set on user classes, which are stored in +/etc/login.conf. This config file also allows limit sets for daemons started +with scripts in the /etc/rc.d directory, which presumably includes Tor. + +To increase the file descriptor limit from its default of 1,024, add the +following to /etc/login.conf: + +tor:\ + :openfiles-max=13500:\ + :tc=daemon: + +Upon restarting Tor, it will be able to open up to 13,500 file descriptors. + +This will work *only* if you are starting Tor with the script /etc/rc.d/tor. If +you're using a custom build instead of the package, you can easily copy the rc.d +script from the Tor port directory. Alternatively, you can ensure that the Tor's +daemon user has its own user class and make a /etc/login.conf entry for it. + +High-bandwidth relays sometimes give the syslog warning: + +/bsd: WARNING: mclpools limit reached; increase kern.maxclusters + +In this case, increase kern.maxclusters with the sysctl command and in the file +/etc/sysctl.conf, as described with kern.maxfiles above. Use 'sysctl +kern.maxclusters' to query the current value. Increasing by about 15% per day +until the error no longer appears is a good guideline. + +Disclaimer +---------- + +Do note that this document is a draft and above information may be +technically incorrect and/or incomplete. If so, please open a ticket +on https://trac.torproject.org or post to tor-relays mailing list. + +Are you running a busy Tor relay? Let us know how you are solving +the out-of-sockets problem on your system. + |