==== iSCSI client ====
=== install iscsi-initiator-utils ===
  # yum install iscsi-initiator-utils
=== iscsiadm command ===
<code>
list
# iscsiadm -m node

logout all
# iscsiadm -m node -U all

session
# iscsiadm -m session
# iscsiadm -m session -P 3

discover
# iscsiadm -m discovery -t st -p <IP>
10.196.241.255:3260,1 iqn.2015-02.oracle.boot:uefi

login
# iscsiadm -m node -T iqn.2015-02.oracle.boot:uefi -l
Logging in to [iface: default, target: iqn.2015-02.oracle.boot:uefi, portal: 10.196.241.255,3260] (multiple)
Login to [iface: default, target: iqn.2015-02.oracle.boot:uefi, portal: 10.196.241.255,3260] successful.

list iSCSI disks
# lsblk

Turn on SCSI/iSCSI error handling lgos
echo -n 1 > /sys/module/libiscsi/parameters/debug_libiscsi_eh
echo -n 0xff > /sys/module/scsi_mod/parameters/scsi_logging_level

Or
scsi_logging_level -s --error 7 --timeout 7 --all 0
</code>


==== targetcli ====

http://linux-iscsi.org/wiki/Targetcli

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/storage_administration_guide/ch24


=== installation ===
  * RHEL7/CentOS7

<code>
yum install targetcli
systemctl status target
systemctl enable target
targetcli
/> ls
o- / ......................................................................................................................... [...]
  o- backstores .............................................................................................................. [...]
  | o- block .................................................................................................. [Storage Objects: 0]
  | o- fileio ................................................................................................. [Storage Objects: 0]
  | o- pscsi .................................................................................................. [Storage Objects: 0]
  | o- ramdisk ................................................................................................ [Storage Objects: 0]
  o- iscsi ............................................................................................................ [Targets: 0]
  o- loopback ......................................................................................................... [Targets: 0]

</code>


=== Create backstores ===

<code>
FILEIO (Linux file-backed storage)  write_back and write_thru
/> /backstores/fileio create file1 /home/tgt/disk1.img 100G write_back=false
Created fileio file1 with size 107374182400
/> ls /backstores/fileio/
o- fileio ..................................................................................................... [Storage Objects: 1]
  o- file1 ................................................................. [/home/tgt/disk1.img (100.0GiB) write-thru deactivated]
    o- alua ....................................................................................................... [ALUA Groups: 1]
      o- default_tg_pt_gp ........................................................................... [ALUA state: Active/optimized]

BLOCK (Linux BLOCK devices)
/> /backstores/block create name=block1 dev=/dev/sdb
Generating a wwn serial.
Created block storage object block_backend using /dev/sdb.

PSCSI(Linux pass-through SCSI devices)

RAMDISK(Linux RAMDISK_MCP)
</code>

=== Configure target ===
<code>
/> iscsi/ 
/iscsi> create iqn.2015-02.oracle.boot:uefi
Created target iqn.2015-02.oracle.boot:uefi.
Created TPG 1.
Global pref auto_add_default_portal=true
Created default portal listening on all IPs (0.0.0.0), port 3260.
/iscsi> ls
o- iscsi .............................................................................................................. [Targets: 1]
  o- iqn.2015-02.oracle.boot:uefi ........................................................................................ [TPGs: 1]
    o- tpg1 ................................................................................................. [no-gen-acls, no-auth]
      o- acls ............................................................................................................ [ACLs: 0]
      o- luns ............................................................................................................ [LUNs: 0]
      o- portals ...................................................................................................... [Portals: 1]
        o- 0.0.0.0:3260 ....................................................................................................... [OK]

</code>

=== configure iSCSI portal ===
<code>
# create a portal
/iscsi> 
/> /iscsi/iqn.2015-02.oracle.boot:uefi/tpg1/portals
/iscsi/iqn.20../tpg1/portals> create

# delete a portal
/iscsi/iqn.20.../tpg1/portals/delete ip_address=0.0.0.0 ip_port=3260
</code>

=== configure LUNs ===
<code>
/> iscsi/iqn.2015-02.oracle.boot:uefi/tpg1/luns/
/iscsi/iqn.20...efi/tpg1/luns> create /backstores/fileio/file1 
Created LUN 0.
</code>

=== Create ACL ===
<code>
/> /iscsi/iqn.2015-02.oracle.boot:uefi/tpg1/acls 
/iscsi/iqn.20...efi/tpg1/acls> create iqn.2015-02.oracle.boot:instance
Created Node ACL for iqn.2015-02.oracle.boot:instance
Created mapped LUN 0.
Created mapped LUN 1.

</code>