# iSCSI on Linux

## Preparation
Install `open-iscsi`, at least on Debian systems.


## Use an iSCSI target from Linux

In our setup a Synology NAS at 172.16.200.19 provides the targets.

First, run
```
   iscsiadm -m discovery -t sendtargets -p 172.16.200.19
```
to discover all provided targets.

You get something like this
```
   172.16.200.19:3260,1 iqn.2000-01.com.synology:nas.Target-GitLab.db1c0541e7
   [fe80::211:32ff:febe:da31]:3260,1 iqn.2000-01.com.synology:nas.Target-GitLab.db1c0541e7
   172.16.200.19:3260,1 iqn.2000-01.com.synology:nas.Target-Bitwarden.db1c0541e7
   [fe80::211:32ff:febe:da31]:3260,1 iqn.2000-01.com.synology:nas.Target-Bitwarden.db1c0541e7
   172.16.200.19:3260,1 iqn.2000-01.com.synology:nas.Target-Nextcloud.db1c0541e7
   [fe80::211:32ff:febe:da31]:3260,1 iqn.2000-01.com.synology:nas.Target-Nextcloud.db1c0541e7
   172.16.200.19:3260,1 iqn.2000-01.com.synology:nas.Target-MariaDB.db1c0541e7
   [fe80::211:32ff:febe:da31]:3260,1 iqn.2000-01.com.synology:nas.Target-MariaDB.db1c0541e7
   172.16.200.19:3260,1 iqn.2000-01.com.synology:nas.Target-Backup.db1c0541e7
   [fe80::211:32ff:febe:da31]:3260,1 iqn.2000-01.com.synology:nas.Target-Backup.db1c0541e7
```

Now, connect to the target using
```
   iscsiadm -m node --targetname "iqn.2000-01.com.synology:nas.Target-Backup.db1c0541e7" \
     --portal 172.16.200.19 --login
```

A new SCSI device will be created. Check the name of the device using ''dmesg''. You see something like this
```
   [16924536.979916] scsi host13: iSCSI Initiator over TCP/IP
   [16924537.010635] scsi 13:0:0:1: Direct-Access     SYNOLOGY iSCSI Storage    4.0  PQ: 0 ANSI: 5
   [16924537.011449] sd 13:0:0:1: Attached scsi generic sg10 type 0
   [16924537.012597] sd 13:0:0:1: [sdj] 209715200 512-byte logical blocks: (107 GB/100 GiB)
   [16924537.012827] sd 13:0:0:1: [sdj] Write Protect is off
   [16924537.012828] sd 13:0:0:1: [sdj] Mode Sense: 43 00 10 08
   [16924537.013111] sd 13:0:0:1: [sdj] Write cache: enabled, read cache: enabled, supports DPO and FUA
   [16924537.013361] sd 13:0:0:1: [sdj] Optimal transfer size 16384 logical blocks > dev_max (8192 logical blocks)
   [16924537.018630] sd 13:0:0:1: [sdj] Attached SCSI disk
```

Now use `fdisk`, `mkfs` and if you like `blkid` on the new device and put it into the `/etc/fstab`.


===== Authenticated target =====

```
    iscsiadm   --mode node  --targetname "iqn.2007-01.org.debian.foobar:CDs"  -p 192.168.0.1:3260 --op=update --name node.session.auth.authmethod --value=CHAP
    iscsiadm   --mode node  --targetname "iqn.2007-01.org.debian.foobar:CDs"  -p 192.168.0.1:3260 --op=update --name node.session.auth.username --value=$Id
    iscsiadm   --mode node  --targetname "iqn.2007-01.org.debian.foobar:CDs"  -p 192.168.0.1:3260 --op=update --name node.session.auth.password --value=$MDP
    iscsiadm   --mode node  --targetname "iqn.2007-01.org.debian.foobar:CDs"  -p 192.168.0.1:3260 --login
```

