OpenBSD and iSCSI part2: the initiator (client)

This is the second article of the serie about iSCSI. In this one, you will learn how to connect to an iSCSI target using OpenBSD base daemon iscsid.

The configuration file of iscsid doesn’t exist by default, its location is /etc/iscsi.conf. It can be easily written using the following:

target1="100.64.2.3"
myaddress="100.64.2.2"

target "disk1" {
    initiatoraddr $myaddress
    targetaddr $target1
    targetname "iqn.1994-04.org.netbsd.iscsi-target:target0"
}

While most lines are really obvious, it is mandatory to have the line initiatoraddr, many thanks to cwen@ for pointing this out when I was stuck on it.

The targetname value will depend of the iSCSI target server. If you use netbsd-iscsi-target, then you only need to care about the last part, aka target0 and replace it by the name of your target (which is target0 for the default one).

Then we can enable the daemon and start it:

# rcctl enable iscsid
# rcctl start iscsid

In your dmesg, you should see a line like:

sd4 at scsibus0 targ 1 lun 0: <NetBSD, NetBSD iSCSI, 0> SCSI3 0/direct fixed t10.NetBSD_0x5c6cf1b69fc3b38a

If you use netbsd-iscsi-target, the whole line should be identic except for the sd4 part which can change, depending of your hardware.

If you don’t see it, you may need to reload iscsid configuration file with iscsictl reload.

Warning: iSCSI is a bit of pain to debug, if it doesn’t work, double check the IPs in /etc/iscsi.conf, check your PF rules on the initiator and the target. You should be at least able to telnet into the target IP port 3260.

Once you found your new sd device, you can format it and mount it as a regular disk device:

# newfs /dev/rsd4c
# mount /dev/sd4c /mnt

iSCSI is far mor efficient and faster than NFS but it has a total different purpose. I’m using it on my powerpc machines to build packages on it. This reduce their old IDE disks usage while giving better response time and equivalent speed.