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gsched(8) [freebsd man page]

GSCHED(8)						    BSD System Manager's Manual 						 GSCHED(8)

NAME
gsched -- control utility for disk scheduler GEOM class SYNOPSIS
gsched create [-v] [-a algorithm] provider ... gsched insert [-v] [-a algorithm] provider ... gsched configure [-v] [-a algorithm] node ... gsched destroy [-fv] node ... gsched reset [-v] node ... gsched { list | status | load | unload } DESCRIPTION
The gsched utility (also callable as geom sched ...) changes the scheduling policy of the requests going to a provider. The first argument to gsched indicates an action to be performed: create Create a new provider and geom node using the specified scheduling algorithm. algorithm is the name of the scheduling algorithm used for the provider. Available algorithms include: rr, which implements anticipatory scheduling with round robin service among clients; as, which implements a simple form of anticipatory scheduling with no per-client queue. If the operation succeeds, the new provider should appear with name /dev/<dev>.sched.. The kernel module geom_sched.ko will be loaded if it is not loaded already. insert Operates as "create", but the insertion is "transparent", i.e. the existing provider is rerouted to the newly created geom, which in turn forwards requests to the existing geom. This operation allows one to start/stop a scheduling service on an already exist- ing provider. A subsequent "destroy" will remove the newly created geom and hook the provider back to the original geom. configure Configure existing scheduling provider. It supports the same options as the create command. destroy Destroy the geom specified in the parameter. reset Do nothing. list | status | load | unload See geom(8). Additional options: -f Force the removal of the specified provider. -v Be more verbose. SYSCTL VARIABLES
The following sysctl(8) variables can be used to control the behavior of the SCHED GEOM class. The default value is shown next to each vari- able. kern.geom.sched.debug: 0 Debug level of the SCHED GEOM class. This can be set to a number between 0 and 2 inclusive. If set to 0 minimal debug information is printed, and if set to 2 the maximum amount of debug information is printed. EXIT STATUS
Exit status is 0 on success, and 1 if the command fails. EXAMPLES
The following example shows how to create a scheduling provider for disk /dev/ada0, and how to destroy it. # Load the geom_sched module: kldload geom_sched # Load some scheduler classes used by geom_sched: kldload gsched_rr # Configure device ada0 to use scheduler "rr": geom sched insert -a rr ada0 # Now provider ada0 uses the "rr" algorithm; # the new geom is ada0.sched. # Remove the scheduler on the device: geom sched destroy -v ada0.sched. SEE ALSO
geom(4), geom(8) HISTORY
The gsched utility first appeared in FreeBSD 8.1. AUTHORS
Fabio Checconi <fabio@FreeBSD.org> Luigi Rizzo <luigi@FreeBSD.org> BSD
July 26, 2012 BSD

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GEOM(8) 						    BSD System Manager's Manual 						   GEOM(8)

NAME
geom -- universal control utility for GEOM classes SYNOPSIS
geom class help geom class list [-a] [name ...] geom class status [-ags] [name ...] geom class load [-v] geom class unload [-v] DESCRIPTION
The geom utility is used to control various GEOM classes. A class has to be aware of geom(8) communication methods, but there are also some standard commands which can be used for existing geom(8) unaware classes. Here is the list of standard commands: help List all available commands for the given class. list Print detailed information (within the given class) about all geoms (if no additional arguments were specified) or the given geoms. This command is only available if the given class exists in the kernel. Additional options include: -a Print information for geoms without providers. status Print general information (within the given class) about all geoms (if no additional arguments were specified) or the given geoms. This command is only available if the given class exists in the kernel. Additional options include: -a When used with -g, print status for geoms without providers. -g Report statuses for geoms instead of providers. -s Produce script-friendly output. load Load the kernel module that implements the given class. This command is only available if the class does not yet exist in the kernel and the file geom_<class>.ko can be found in one of the directories specified in kern.module_path sysctl. unload Unload the kernel module which implements the given class. This command is only available if the given class is loaded as a kernel module. Class-specific commands are implemented as shared libraries which are stored in /lib/geom/ directory and are loaded via dlopen(3) function when the class name is known. When a class-specific shared library exists, a direct utility should also be available under the name of gclass. Currently available classes which are aware of geom(8): o CACHE o CONCAT o ELI o JOURNAL o LABEL o MIRROR o MOUNTVER o MULTIPATH o NOP o PART o RAID o RAID3 o SCHED o SHSEC o STRIPE o VIRSTOR ENVIRONMENT
The following environment variables affect the execution of geom: GEOM_LIBRARY_PATH Specifies the path where shared libraries are stored instead of /lib/geom/. Multiple paths can be specified with a colon- separated list of paths. EXIT STATUS
Exit status is 0 on success, and 1 if the command fails. EXAMPLES
The following example shows how to set up a stripe on three disks for automatic configuration: geom stripe label -v -s 65536 data /dev/da0 /dev/da1 /dev/da2 or: gstripe label -v -s 65536 data /dev/da0 /dev/da1 /dev/da2 Print the list of all providers from the DISK class: geom disk list Unload a kernel module which implements the MD class: geom md unload SEE ALSO
libgeom(3), geom(4), gcache(8), gconcat(8), geli(8), gjournal(8), glabel(8), gmirror(8), gmountver(8), gmultipath(8), gnop(8), gpart(8), graid3(8), gsched(8), gshsec(8), gstripe(8), gvirstor(8) HISTORY
The geom utility appeared in FreeBSD 5.3. AUTHORS
Pawel Jakub Dawidek <pjd@FreeBSD.org> BSD
January 5, 2011 BSD

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