The latest half-width Cisco UCS B-series servers are beautiful pieces of machinery. In such a small footprint it is possible to get two processors each with 10 cores and 20 threads. In addition, the blade supports an amazing 512GB of memory and features the ability to support up to two hot-swappable SSD drives.

Unfortunately, while working with this bleeding edge technology, I have run into several limitations. I would like to share some of the limitations I have experienced in the workarounds available today.

B230s running vSphere 4.x require upgraded HBA and NIC drivers - While it is possible to install vSphere 4.x without upgrading the drivers, lots of error messages will be seen in the ESXi logs and poor performance will likely be experienced. As an example, if you present and connect to a LUN and then remove it on the storage side, the ESXi host will become unresponsive. However, if you upgrade the drivers, this issue is not experienced.

B230s require UCS B-series firmware version >=1.4(3q) and UCS B-series BIOS firmware version >=1.4.3d to support EVC Intel mode 32nm i7 - If you are running a UCS B-series BIOS firmware version under 1.4(3d), which is part of the UCS B-series firmware version 1.4(3q), the highest version of EVC Intel mode possible is i7. The reason for this is because the Advanced Encryption Standard (AES) instructions are disabled and are also not exposed to the user to be enabled. The B200 blades did not experience this issue and as such I had them configured as 32nm i7. In order to keep everything consistent and to prevent the need of rebooting VMs, I opted to install UCS + UCS B-series firmware 1.4(3q) from the beginning.

B230s running vSphere 4.x with EVC mode only support VMware Fault Tolerance if running mode i7 or older - This means even if running UCS B-series BIOS firmware 1.4(3q) EVC Intel mode 32nm i7 cannot be selected if fault tolerance is to be used. There is not workaround to this issue at this time.

B230s are not supported on vSphere 5 (as of 9/20/11 supported on UCS firmware 2.0) - I was able to successfully vSphere 5 on the B230 servers, however I experienced lots of errors on the ESXi host and odd host issues including poor performance. The odd host issues included vSphere HA configuration errors, hosts disconnecting for vCenter Server, sluggish vSphere client operations, and sluggish VMs. I later learned that the B230s are not on the VMware Compatibility Support Matrix. After talking with VMware support I was told the B230s were not supported due to the need for updated drivers and that they would be fixed "soon".

*** UPDATE: I just learned from Cisco that the B230s will support vSphere 5.0 on UCS firmware version 2.0. At this time, there is no plan to support the B230s with vSphere 5.0 on any version of UCS firmware under 2.0.

*** UPDATE2: I adjusted the firmware terminology to avoid confusion. In 1.4 the switch and server firmware were separated resulting in the need to perform two different downloads. I prefer to keep the switch and server firmware in sync and as such refer to them collectively as UCS firmware. The distinction between switch and server firmware is specifically important for the EVC issue as it is the blade firmware (specifically the BIOS firmware) that causes the issue and is what needs to be upgraded.

*** UPDATE3: UCS firmware version 2.0 has been released! The VMware compatibility matrix now shows support for the B230s on vSphere 5 using UCS firmware 2.0.

*** UPDATE (2012-01-26): Please be advised of the following new caveats:

1. B230-M2 is only supported on ESX(i) version greater than 4.1 (i.e. U1, U2, or 5.0) - As of December 14
2. B230-M2 is only supported on ESX(i) 4.1 U2 running UCS version 2.0 or greater (4.1 U1 is supported on UCS version 1.4.x) - Officially supported January 17
3. C1E is enabled by default and causes processor halted messages that may lead to ESX(i) hosts disconnecting from vCS. This can be changed in the BIOS service profile in UCS versions 2.0 and greater, but can only be changed manually via the console on 1.4.x - See my blog post on 2012-01-26 for more details.