Linux OS service ‘iscsid’

Service Name

iscsid

Description

The iscsid (Internet Small Computer Systems Interface) service implements the control path of iSCSI protocol, plus some management facilities. For example, the daemon could be configured to automatically re-start discovery at startup, based on the contents of the persistent iSCSI database.

ISCSI is a protocol to access remote SCSI disks via the network. The major and huge storage devices, like HITACHI SANRISE or EMC, have the function of an iSCSI server – you can connect these storage devices by using iSCSI protocol via the network. However, iSCSI needs a wider bandwidth of the network and is slower and less secure than a SCSI device connected to the machine directly. Therefore this protocol is used only for special applications.

The iscsi-initiator-utils RPM package provides the /sbin/iscsid daemon and its configuration files.

The features and behavior available with the iscsid daemon are controlled by a system-wide configuration /etc/iscsi.conf file. A default file is provided with the RPM package but may be edited to suit local requirements. A full description of configuration options may be read using the online iscsi.conf documentation.

Nature

Daemon service to run the iscsid daemon.

Service Control

To manage the iscsid service on demand, use the service tool or run the /etc/init.d/iscsi script directly:

# service iscsi help
Usage: /etc/init.d/iscsi { start | stop | restart | status | reload }
# /etc/init.d/iscsi help
Usage: /etc/init.d/iscsi { start | stop | restart | status | reload }

The available commands are:

command Purpose
start Start the iscsid daemon.
stop Stop the iscsid daemon.
restart Equivalent to a stop and then a start command sequence.
reload Force the iscsid daemon to re-read its configuration files without a service interruption.
status If the iscsid daemon is running, report its PID (Process ID). If not running, report that, too.

Configuration

To manage the iscsi service at boot time, use chkconfig tool:

# /sbin/chkconfig --list iscsi
iscsi 0:off 1:off 2:off 3:off 4:off 5:off 6:off

Enable the service to start at boot and verify again.

# /sbin/chkconfig iscsi on
# /sbin/chkconfig --list iscsi
iscsi 0:off 1:off 2:on 3:on 4:on 5:on 6

The configuration file is /etc/iscsi.conf. There are comments that document the various parameters. To connect to an iscsi-server, at least the server must be configured and below parameters must be defined in the configuration file :

DiscoveryAddress=[iscsi target IP] 
OutgoingUserName=[username] 
OutgoingPassword=[password] 
LoginTimeout=15
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