In my previous post I explained how SVMotion saved the day, this blog post is about the need for storage fabric redundancy. Storage fabric/network redundancy makes simple upgrades work without the need to power off any VMs or virtualization hosts. My recent upgrade to a Brocade 240E went smoothly once I could access the device.
At the time of the upgrade I started with two Compaq StorageWorks SANSwitch 2/8-EL (Brocade Silkworm) with full enterprise licenses. I am going to a single Brocade 240E with all ports licensed. What going from redundant to non-redundant fabric? Well I need a 4GB fabric and will get the second 240E when I can find/afford one with all 16 ports active.
Instead I planned on zoning half the switch for ZoneA and half for ZoneB, thereby maintaining some level of redundancy at the switch port, HBA, SAN level but without the multiple switch redundancy I had previously (at least for now).
But before I could do any of this, I had to access the Brocade 240E and to do this, you either need to access it via IP 10.77.77.77 which is the default network or via a Serial cable. I tried both and due to a routing issue could not get to the IP so defaulted to the serial port. However a regular Belkin serial cable would not work. Since I did not have a Brocade cable handy I had to find an alternative. My older Silkworms had no issues but I only connected to them via a serial switch box.
So I put a serial switch box inline between two serial cable and viola, I could now access the Brocade 240E without the Brocade serial cable. I still think this is odd as the switch does not do anything funny. Either way I was then able to connect, use the Brocade EZSwitchSetup software to configure my zoning.
Once a valid IP address was added to the Brocade 240E, and other standard configuration options were set, I then went to configure zoning. To do what I wanted to do, which was to zone based on ports, I had to use Advanced zoning. In the Advanced Zoning configuration screens I assigned ports 0-7 to ZoneA and 8-15 to ZoneB. Now my switch can act like two switches.
Time to put the Brocade 240E into the fabric. I simply disconnected the cables from my backup 2/8-EL switch and put all its cables into the ports for ZoneB. I did place the fibre cable for the SAN into port 8. Once I ensured I had valid light it was time to proceed to the active switch.
Now time to move the cables from the active switch. This was accomplished by moving the cable for the SAN into port 0 of the Brocade 240E, then once everything failed over to the ZoneB, I moved the rest of the cables to the ports within ZoneA. Once light was established all was well.
Downtime: 0 minutes 0 seconds
Redundant Storage Networks whether IP or fabric based is a requirement for your virtual environment. Whether it is a simple switch upgrade or failed hardware, redundancy will keep your systems alive. Maintaining this redundancy with proper zoning when you have a single switch will also add another layer of protection.
Edward L. Haletky, aka Texiwill, is an author, analyst, developer, technologist, and business owner. Edward owns AstroArch Consulting, Inc., providing virtualization, security, network consulting and development and TVP Strategy where he is also an Analyst. Edward is the Moderator and Host of the Virtualization Security Podcast as well as a guru and moderator for the VMware Communities Forums, providing answers to security and configuration questions. Edward is working on new books on Virtualization.