I recently had cause to try out COMSTAR for the first time, and I thought I'd write up the steps needed. Unfortunately, it's considerably more complex than the fall-over-easy shareiscsi=on ZFS feature.

Configuring the COMSTAR server

First install the storage-server packages and enable the services:

# svcadm enable -r stmf
# svcadm enable -r iscsi/target

We want to create a target group for each of our xVM guests, each of which will have one LUN in it. After creating the LUN, we define a "view" that allows that LUN to be visible for that target group:

# stmfadm create-tg domu-226
# zfs create -V 15G export/domu-226
# stmfadm create-lu /dev/zvol/rdsk/export/domu-226
Logical unit created: 600144F0C73ABF0F00004AD75DF2001A
# stmfadm add-view -t domu-226 600144F0C73ABF0F00004AD75DF2001A

Now we need to create the iSCSI target for this target group, that has our single LUN in it.

# itadm create-target -l domu-226
Target iqn.1986-03.com.sun:02:b8596bb9-9bb9-40e9-8cda-add6073ece46 successfully created

Here (finally) is our iSCSI Alias we can use in the clients. But we're not done yet. By default, this target will be able to see all LUNs not in a target group. So we need to make it a member of our domu-226 target group:

# stmfadm add-tg-member -g domu-226 iqn.1986-03.com.sun:02:b8596bb9-9bb9-40e9-8cda-add6073ece46
# stmfadm list-tg -v
Target Group: domu-226
        Member: iqn.1986-03.com.sun:02:b8596bb9-9bb9-40e9-8cda-add6073ece46

Configuring the iSCSI initiator (client)

We do this in the usual manner:

# svcadm enable -r svc:/network/iscsi/initiator:default
# iscsiadm add discovery-address 10.6.70.43:3260
# iscsiadm modify discovery --sendtargets enable

Installing a guest onto the LUN

We went through the above gymnastics so we can have a human-readable Alias for each of the domu's root LUNs. So now we can do:

# virt-install --paravirt --name domu-226 --ram 1024 --os-type solaris --os-variant opensolaris \
  --location nfs:10.5.235.28:/export/nv/x/latest --network bridge,mac=00:14:4f:0f:b5:3e \
  --disk path=/alias/domu-226,driver=phy,subdriver=iscsi \
  --nographics

Tags: OpenSolaris Xen xVM COMSTAR