Set up an iscsi storage

From LinuxIntro
Jump to: navigation, search

iSCSI is a protocol that allows you to connect to block-oriented storage over the IP-network. To have an ISCSI target, you do not need to buy an enterprise-class ISCSI storage, you can start an ISCSI target as service on your computer. This is especially useful when running e.g. cluster tests on shared storage.

Contents

QuickStart

SUSE Linux Enterprise server 10

In this chapter, we will set up an ISCSI target and connect to it

Check your state

See how many block devices you have attached:

hwinfo --block --short

Set up a target

  • start yast2
  • chose Miscellaneous->iSCSI target
  • continue as instructed, if prompted, allow to install the package iscsitarget

Set up an initiator

  • start yast2
  • chose Miscellaneous->iSCSI initiator
  • continue as instructed, if prompted, allow to install the package openiscsi

Check if it worked

See how many block devices you have attached:

hwinfo --block --short

It must be more than before

generic

In this chapter we will set up an iscsi target and test it by installing an iscsi initiator.

Set up a target

tar xvfz iscsitarget-0.4.15.tar.gz
cd iscsitarget-0.4.15
make && make install

on problems see the article Compiling.

  • create a configuration for your service:

/etc/ietd.conf

Target iqn.2007-12.local.net:storage.lvm
       Lun 0 Path=/dev/hdb
  • start the service
/etc/init.d/iscsi-target start
  • verify the service is running
$ lsof -i
[...]
ietd      8692   root    7u  IPv6  36856       TCP *:iscsi-target (LISTEN)
ietd      8692   root    8u  IPv4  36857       TCP *:iscsi-target (LISTEN)

Set up an initiator

To set up an iscsi initiator, install the openiscsi package. Then, discover your targets. Let's assume the IP-address of your target is 192.168.0.5

$ iscsiadm -m discovery -t st -p 192.168.0.5 
[fa084c] 192.168.0.5:3260,1 iqn.2001-04.com.example:storage.disk2.sys1.xyz
[3727f9] 127.0.0.1:3260,1 iqn.2001-04.com.example:storage.disk2.sys1.xyz
$ iscsiadm -m node
[fa084c] 192.168.0.5:3260,1 iqn.2001-04.com.example:storage.disk2.sys1.xyz
[3727f9] 127.0.0.1:3260,1 iqn.2001-04.com.example:storage.disk2.sys1.xyz

You know now you have a target named iqn.2001-04.com.example:storage.disk2.sys1.xyz Now have a look what drives you have attached:

$ hwinfo --block --short
disk:
  /dev/sda             VMware Virtual S
  /dev/sdb             IET VIRTUAL-DISK
partition:
[...]

Now connect your iscsi target:

$ iscsiadm -m node -T iqn.2001-04.com.example:storage.disk2.sys1.xyz -p 192.168.0.5:3260 --login

And find a new device in your list:

$ hwinfo --block --short
disk:
  /dev/sda             VMware Virtual S
  /dev/sdb             IET VIRTUAL-DISK
  /dev/sdc             IET VIRTUAL-DISK
partition:
[...]

TroubleShooting

Best idea is probably to check if the iSCSI server is alive. To do this, the iSCSI port 3260 must answer. In the following example there is no iSCSI server running or the port is blocked by the firewall:

# telnet localhost 3260
Trying ::1...
telnet: connect to address ::1: Connection refused
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused

In this case stop your firewall and make sure the iSCSI service is started.

See also