devreserv(1m) [opensolaris man page]
devreserv(1M) System Administration Commands devreserv(1M) NAME
devreserv - reserve devices for exclusive use SYNOPSIS
devreserv [key [device-list]...] DESCRIPTION
devreserv reserves devices for exclusive use. When the device is no longer required, use devfree to release it. devreserv reserves at most one device per device-list. Each list is searched in linear order until the first available device is found. If a device cannot be reserved from each list, the entire reservation fails. When devreserv is invoked without arguments, it lists the devices that are currently reserved and shows to which key it was reserved. When devreserv is invoked with only the key argument, it lists the devices that are currently reserved to that key. OPERANDS
The following operands are supported: device-list Defines a list of devices that devreserv will search to find an available device. The list must be formatted as a single argument to the shell. key Designates a unique key on which the device will be reserved. The key must be a positive integer. EXAMPLES
Example 1 Reserving a Floppy Disk and a Cartridge Tape The following example reserves a floppy disk and a cartridge tape: $ key=$$ $ echo "The current Process ID is equal to: $key" The Current Process ID is equal to: 10658 $ devreserv $key diskette1 ctape1 Example 2 Listing All Devices Currently Reserved The following example lists all devices currently reserved: $ devreserv disk1 2423 diskette1 10658 ctape1 10658 Example 3 Listing All Devices Currently Reserved to a Particular Key The following example lists all devices currently reserved to a particular key: $ devreserv $key diskette1 ctape1 EXIT STATUS
The following exit values are returned: 0 Successful completion. 1 Command syntax was incorrect, an invalid was option used, or an internal error occurred. 2 Device table or device reservation table could not be opened for reading. 3 Device reservation request could not be fulfilled. FILES
/etc/device.tab /etc/devlkfile ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Availability |SUNWcsu | +-----------------------------+-----------------------------+ SEE ALSO
devfree(1M), attributes(5) NOTES
The commands devreserv and devfree are used to manage the availability of devices on a system. Their use is on a participatory basis and they do not place any constraints on the actual access to the device. They serve as a centralized bookkeeping point for those who wish to use them. Devices which have been reserved cannot be used by processes which utilize the device reservation functions until the reserva- tion has been canceled. However, processes that do not use device reservation may use a device that has been reserved since such a process would not have checked for its reservation status. SunOS 5.11 5 Jul 1990 devreserv(1M)
Check Out this Related Man Page
fence_scsi(8) System Manager's Manual fence_scsi(8) NAME
fence_scsi - I/O fencing agent for SCSI persistent reservations SYNOPSIS
fence_scsi [OPTION]... DESCRIPTION
fence_scsi is an I/O fencing agent that uses SCSI-3 persistent reservations to control access to shared storage devices. These devices must support SCSI-3 persistent reservations (SPC-3 or greater) as well as the "preempt-and-abort" subcommand. The fence_scsi agent works by having each node in the cluster register a unique key with the SCSI devive(s). Once registered, a single node will become the reservation holder by creating a "write exclusive, registrants only" reservation on the device(s). The result is that only registered nodes may write to the device(s). When a node failure occurs, the fence_scsi agent will remove the key belonging to the failed node from the device(s). The failed node will no longer be able to write to the device(s). A manual reboot is required. Keys are either be specified manually (see -k option) or generated automatically (see -n option). Automatic key generation requires that cman be running. Keys will then be generated using the cluster ID and node ID such that each node has a unique key that can be determined by any other node in the cluster. Devices can either be specified manually (see -d option) or discovered automatically. Multiple devices can be specified manually by using a comma-separated list. If no devices are specified, the fence_scsi agent will attempt to discover devices by looking for cluster volumes and extracting the underlying devices. Devices may be device-mapper multipath devices or raw devices. If using a device-mapper multipath device, the fence_scsi agent will find the underlying devices (paths) and created registrations for each path. OPTIONS
-o action Fencing action. This value can be "on", "off", or "status". All actions require either a key (see -k option) or node name (see -n option). For "on", the agent will attempt to register with the device(s) and create a reservation if none exists. The "off" action will attempt to remove a node's key from the device(s). The "status" action will report whether or not a node's key is currently register with one or more of the devices. The default action if "off". -d devices List of devices to use for current operation. Devices can be comma-separated list of raw device (eg. /dev/sdc) or device-mapper mul- tipath devices (eg. /dev/dm-3). Each device must support SCSI-3 persistent reservations. -f logfile Log output to file. -n nodename Name of the node to be fenced. The node name is used to generate the key value used for the current operation. This option will be ignored when used with the -k option. -k key Key to use for the current operation. This key should be unique to a node. For the "on" action, the key specifies the key use to register the local node. For the "off" action, this key specifies the key to be removed from the device(s). -a Use the APTPL flag for registrations. This option is only used for the "on" action. -h Print out a help message describing available options, then exit. -v Verbose output. -V Print out a version message, then exit. STDIN PARAMETERS
agent = "param" This option is used by fence_node(8) and is ignored by fence_scsi. nodename = "param" Same as -n option. action = "param" Same as -o option. devices = "param" Same as -d option. logfile = "param" Same as -f option key = "param" Same as -k option. aptpl = "1" Enable the APTPL flag. Default is 0 (disable). SEE ALSO
fence(8), fence_node(8), sg_persist(8), vgs(8), cman_tool(8), cman(5) fence_scsi(8)