Iscsi

Links

• http://nil.uniza.sk/linux-howto/linux-mint-mouting-freenas-iscsi-disk
• iscsiadm command examples
• Scsi-target-utils Quickstart Guide
• Creating and managing iSCSI targets
• https://wiki.archlinux.org/index.php/TGT_iSCSI_Target
• iSCSI on ESXCLI
• https://wiki.archlinux.org/index.php/ISCSI/tgt
• https://ask.openstack.org/en/question/30299/how-to-resize-an-instance-residing-on-a-block-storage-volume/
• targetcli
• https://www.truenas.com/community/resources/why-iscsi-often-requires-more-resources-for-the-same-result.41/
• Share ZFS volumes via iscsi
• iSCSI server with tgt (cheatsheet)

Implementations

Features comparison between Linux SCSI targets

IET

iSCSI Enterprise Target

• ietd
• ietadm
• iscsitarget
• iscsid

LIO

• targetcli

SCST

iSCSI Target Driver

• scst

STGT

Predecessor of LIO

ISTGT

iSCSI Target

FreeBSD/Linux

• istgtcontrol and friends

Comstar

Commands:

• itadm
• stmfadm

TGT

Linux iSCSI Target

• tgtd
• tgdadm

open-iscsi

• iscsiadm?

FreeBSD

FreeBSD native iscsi target

• iscsid
• iscsictl

And there's tgt

FAQ

On ISCSI client

Get WWID

/lib/udev/scsi_id -g -u -d /dev/sda

List sessions

iscsiadm -m session

List targets and SIDs

iscsiadm -m session -P 3|egrep "Target|SID"

what /dev/ disk is on the target?

Where 7 is SID

iscsiadm -m session -P 3 -r 7 | grep "Attached scsi disk"

Attached scsi disk sde State: running

Or look at

ls /dev/disk/by-path/

Find targets

iscsi_discovery 192.168.100.32
    

Please logout from all targets on 192.168.178.3:3260 before trying to run discovery on that portal

??

List connected targets

iscsiadm -m session -P 3

iscsiadm -m session -P 3 |  grep -E "^Target|SID:|Attached"

or ??

tgtadm --lld iscsi --op show --mode conn --tid 1

but that needs more work

List targets

iscsiadm -m discovery -t sendtargets -p 192.168.100.32

Connect to target

iscsiadm -m node --targetname="iqn.2018-5.mynet:drbd0" --portal "192.168.100.32" --login

if you get things like "iscsiadm: No records found" try a thing like

iscsiadm --mode node -l all

Disconnect from target

iscsiadm -m node -T iqn.2018-5.mynet:drbd0 [-p 192.168.100.32] -u

Delete target

iscsiadm -m node -T iqn.2018-5.mynet:drbd0 [-p 192.168.100.32] -o delete

Get a lot of info about target

not working?

iscsiadm -m node -T iqn.2018-5.mynet:drbd0 -p 192.168.100.32

Show session id

iscsiadm -m session -P 1

 

Rescan ??

iscsiadm -m node --targetname="foo.bar" -R

Disconnect all targets

iscsiadm --mode node -u all

Rescan session

not right?

iscsiadm -m session -r SID --rescan⁠

iscsiadm: Could not log into all portals

??

On server

list targets

tgtadm --lld iscsi --mode target --op show

NOTE check for LUN: 1 or higher!

list connected targets

To list all connections to target with id 1:

tgtadm --lld iscsi --mode conn --op show --tid 1

And disconnect target:

tgtadm --lld iscsi --op delete --mode conn --tid 1 --sid 2 --cid 0

Create iscsi target and Lun

tgtadm --lld iscsi --mode target --op new --tid=1 --targetname iqn.2009-02.com.example:for.all

and then add device

tgtadm --lld iscsi --mode logicalunit --op new --tid 1 --lun 1 -b /var/tmp/iscsi-disk1

Delete iscsi target and Lun

tgtadm --lld iscsi --mode logicalunit --op delete --tid 1 --lun 1
tgtadm --lld iscsi --mode target --op delete --tid=1

Reload tgtd configuration

tgt-admin --update ALL

or

tgt-admin --update your.irqn.string

Show tgdt config

tgt-admin --dump

Grow/resize target

After resizing the target (lvresize or whatever)

tgt-admin --update tid=xx -v -f

Show targets

tgt-admin -s

Show target config

This includes target parameters

tgtadm --lld iscsi -o show -m target --tid=1

The disk contains an unclean file system (0, 0).

Metadata kept in Windows cache, refused to mount.
Falling back to read-only mount because the NTFS partition is in an
unsafe state. Please resume and shutdown Windows fully (no hibernation
or fast restarting.)

ntfsfix /dev/sdc1

On ESXi

• esxcli iscsi
• Use iSCSI storage on esxi

Mounting iscsi datastore

• How to mount an iSCSI datastore in ESXI CLI

esxcfg-volume -l

esxcfg-volume -m

List connected targets

esxcli iscsi session list 

Do the iSCSI Discovery for the iSCSI Host Bus Adapter.

esxcli iscsi adapter discovery rediscover --adapter vmhba64

List targets

esxcli iscsi adapter target list

Some commands

esxcli storage core path list
esxcli storage core adapter rescan --adapter=vmhba64

esxcli iscsi adapter param get -A vmhba64
esxcli iscsi adapter list

Error messages

connection1:0: detected conn error (1020)

These messages are seen when an iSCSI connection times out (1011 means timeout on initiator side and 1020 means the target dropped the connection)

tgtadm: failed to send request hdr to tgt daemon, Transport endpoint is not connected

tgtd not running :)

 

tgtd: iser_ib_init(3436) Failed to initialize RDMA; load kernel modules?

comment out default-driver

 

iscsiadm: No portals found

ACL issue, try something like

tgtadm --lld iscsi --op bind --mode target --tid 6 -I ALL

 

iscsiadm: No records found

Try

iscsiadm -m discovery -t sendtargets -p <ip-address>

Problems

Lun:1 is lost

Normally you expect to find on client

scsi9 Channel 00 Id 0 Lun: 0
scsi9 Channel 00 Id 0 Lun: 1
      Attached scsi disk sdc          State: running

if last two lines are missing: Check on server

tgtadm --lld iscsi --mode target --op show

you might find

LUN: 1
...
Backing store path: ...

missing, so add that again:

tgtadm --lld iscsi --op new --mode logicalunit --tid 4 --lun 1 -b /dev/zvol/tank/iscsi4