NAME
targets —
configuration file for iSCSI
targets
SYNOPSIS
DESCRIPTION
The
targets file describes the iSCSI storage which is
presented to iSCSI initiators by the
iscsi-target(8) service. A
description of the iSCSI protocol can be found in
Internet
Small Computer Systems Interface RFC 3720.
Each line in the file (other than comment lines that begin with a
‘#’) specifies an extent, a device (made up of extents or other
devices), or a target to present to the initiator.
Each definition, an extent, a device, and a target, is specified on a single
whitespace delimited line.
The
extent definition specifies a piece of storage that
will be used as storage, and presented to initiators. It is the basic
definition for an iSCSI target. Each target must contain at least one extent
definition. The first field in the definition is the extent name, which must
begin with the word “extent” and be followed by a number. The next
field is the file or
NetBSD device which will be used
as persistent storage. The next field is the offset (in bytes) of the start of
the extent. This field is usually 0. The fourth field in the definition is the
size of the extent. The basic unit is bytes, and the shorthand
KB,
MB,
GB,
and
TB can be used for kilobytes (1024 bytes), megabytes
(1024 kilobytes), gigabytes (1024 megabytes), and terabytes (1024 gigabytes)
respectively. It is possible to use the word “size” to use the
full size of the pre-existing regular file given in the extent name.
The
device definition specifies a LUN or device, and is
made up of extents and other devices. It is possible to create hierarchies of
devices using the device definition. The first field in the definition is the
device name, which must begin with the word “device” and be
followed by a number. The next field is the type of resilience that is to be
provided by the device. For simple devices,
RAID0
suffices. Greater resilience can be gained by using the
RAID1 resilience field. Following the resilience field
is a list of extents or other devices. Large devices can be created by using
multiple RAID0 extents, in which case each extent will be concatenated.
Resilient devices can be created by using multiple RAID1 devices or extents,
in which case data will be written to each of the devices or extents in turn.
If RAID1 resilience is used, all the extents or sub-devices must be the same
size. Please note that RAID1 recovery is not yet supported by the
iscsi-target(8) utility.
An extent or sub-device may only be used once.
The
target definition specifies an iSCSI target, which is
presented to the iSCSI initiator. Multiple targets can be specified. The first
field in the definition is the target name, which must begin with either of
the words “target” or “lun” and be followed by a
number. Optionally, if a target is followed by an “=” sign and
some text, the text is taken to be that of the iSCSI Qualified Name of the
target. This IQN is used by the initiator to connect to the appropriate
target. The next field is a selector for whether the storage should be
presented as writable, or merely as read-only storage. The field of
“rw” denotes read-write storage, whilst “ro” denotes
read-only storage. The next field is the device or extent name that will be
used as persistent storage for this target. The fourth field is a
slash-notation netmask which will be used, during the discovery phase, to
control the network addresses to which targets will be presented. The magic
values “any” and “all” will expand to be the same as
“0/0”. If an attempt is made to discover a target which is not
allowed by the netmask, a warning will be issued using
syslog(3) to make administrators
aware of this attempt. The administrator can still use tcp wrapper
functionality, as found in
hosts_access(5) and
hosts.deny(5) to allow or
deny discovery attempts from initiators as well as using the inbuilt netmask
functionality.
FILES
- /etc/iscsi/targets
- the list of exported storage targets
SEE ALSO
syslog(3),
hosts.deny(5),
hosts_access(5),
iscsi-target(8)
HISTORY
The
targets file first appeared in
NetBSD
4.0.