Implementing iSCSI on AIX with Storwize V7000 (V7000U)
meyawi 270002D6NU Visits (7050)
When properly configured, an AIX server can act as :
In our case, iSCSI initiator will be an AIX 7.1 (7100-00-03-1115) and the iSCSI target will be a Storwize V7000 Unified.
Configuring iSCSI on V7000U
Let’s check iSCSI configuration on the Storwize.
Port configuration IP
In this example, I used port1 of both nodes, but consider dedicating port2 instead in order to separate management traffic and iSCSI traffic.
iSCSI configuration on AIX
From AIX node, we’ll check that we can ping both iSCSI ports IP address of the Storwize.
Now we could configure the iSCSI software initiator.
meyawi.com@root:/> lsdev|grep iscsi iscsi0 Available iSCSI Protocol Device
We’ll use the file Discovey Policy, which means that information about targets are stored in a file (disc_filename) : /etc/iscsi/targets
The initiator name could be changed if needed :
chdev –l iscsi0 –a init
Now, let’s update /etc/iscsi/targets with V7000U iSCSI target ports information.
Each target is defined by 3 fields minimum as follows : HostNameOrAddress PortNumber iSCSIName
192.168.251.121 3260 iqn.
V7000U : Host creation + Volume mapping
We have to create a new iSCSI host within the V7000U admin interface :
Our AIX test node is named londres-test and the initiator port adress is : iqn.
The initiator is found on iscsi0 (lsattr –El iscsi0).
Once the host created, we have to create a volume and map it to our host :
AIX : Disk Discovery & Multipathing
Now that everything seems to be ok, execute cfgmgr to discover the new mapped disk.
Surprise !! Instead of one new disk, we see 2 new disks. So what happened ?!
In fact, it’s the same disk, but multipathing is disabled so the volume appears to be 2 separate devices, one from each V7000U node :
The host selects one device to perform I/O to the volume, which corresponds to a particular IP address at a Storwize V7000 node port.
If a connection between the host and this Storwize V7000 port is broken, there is no high availibility and an I/O error is recorded on host.
At the time of writing, it seems that iSCSI multipathing is not supported on AIX hosts with software initiator
I tried on a linux redhat distribution (RHEL5), and according to documentation, multipathing seems to be supported :
AIX : iSCSI Initiator Considerations