In one of my last post I have discussed about Microsoft iSCSI Target Software 3.3. You can use this software to convert your (old) servers especially where you can populate a bunch of high capacity SATA/SAS HDD to convert the same to an IP SAN. Well this kind of scenario may be applicable for LAB/SMB business units where we don’t want to buy/spend lots of money for a specialized storage box. Well these days a lot of low cost SAS based DAS or IP-SANs are available in market with specialized storage features. So for usability you have to decide where you can use this kind of setup. Lets build a highly available storage, kind of active passive iscsi storage controllers ;-). Hope you are not getting confused with Building a MS Failover Cluser using MS iSCSI Target Software.
My Design Decisions & Blueprint
In my environment I used to have a Dell MD3000 SAS based direct storage box. I can connect 4 Servers directly without any path redundancy to this storage box & 2 Servers with 2-redundant path. But I have bunch of old (10) Dell Poweredge servers in my lab (generated out of dc consolidation project), I would like to repurpose them in my LAB & for some low priority low production purpose in my headquarter. Well none of my servers or devices is having warranty any longer. Renewing warranty or buying new hardware is out of budget. So I thought let’s do it this way…..
- Apart from 1st 2 HDD I have pulled out all HDDs from Dell PE Servers & Populated remaining empty slots of MD 3000i. And made sure these HDDs are compatible with the storage box. Easy way of doing is install MD 3000 storage manager software & verify from the console software. I have discussed the installation & MD 3000 config step in one of my old post. It is here.
On server front I have decided
- Two Node Windows Failover cluster with complete redundant path
I will utilize this cluster for Two Roles
- Hyper-V Failover Cluster Role;
With one Clustered Shared Volume to Host Less Critical LOB Application Virtual Machine
Ms iSCSI Target Cluster Role;
with multiple clustered LUNs to Host virtual disks. These virtual disks will be presented to other Stand Alone Poweredge Servers through iSCSI Target using iSCSI technique. After wards I can use the same disk to host multiple virtual machines or I can use the same disk as a pass-through disk to your existing VMs. I prefer them to use as pass-through disks. . If I could use these Disks to host multiple Virtual Machine VHDs, there must be a lot of virtual translations i.e. VHDs inside -> VHDs inside -> NTFS partition.
- Hyper-V Failover Cluster Role;
Note: In next version of iSCSI Target I would like to see direct use of physical disk not VHDs inside NTFS partition. I could have also used those 8 Stand Alone Poweredge Servers to again create a hyper-v cluster using exported iSCSI volumes. But I never thought of that as a requirement because I will be using them in my test lab. Even if one server fails I will re-assign iSCSI exported virtual disk (LUN) to another node & start VMs over there. We can design all components in a better way to provide more performance like one VHD in one LUN, redundant network connections etc.
So to start with I have carved out 3 LUNs from the MD3000 & assigned to Node1 & Node2
- Quorum LUN: 1GB
- CSV LUN: 550GB
- iSCSI Target LUN: 550GB
Network Design is one of the key components to achieve this; so I have decided on below NICs for Failover Cluster Nodes. I am flexible because it is a LAB & low priority production env.
- Management & Virtual Machine Network: 1 NIC/node with X.X.X.X subnet
- Cluster Communication & Live Migration Network: 1 NIC/node with Y.Y.Y.Y subnet
- iSCSI Target Network: 1 NIC/node with Z.Z.Z.Z subnet (this is the adapter through which iSCSI Traffic will be coming in from Standalone LAB Hyper-v Server’s iSCSI initiators)