For a customer I just installed a vSphere 5.1 essentials environment. Two IBM x3650M4 hosts connected over ONE path to an IBM DS3512 storage. Soon a second HBA will be added to the configuration and we'll have two paths.
Before installing I checked the BIOS versions of the ESXi hosts. According to the VMware HCL, the BIOS version should be IBM-[VVE112H]. According to the IMM, the hosts are running
UEFI (Active) 1.21 VVE120EUS 11 Oct 2012
The problem we're experiencing is that all disk actions are very slow. In the vmkernel.log I can see a lot of path failovers that would explain why the system is slow. (See logs at end of this post).
When searching for these errors, I found this community post: http://communities.vmware.com/thread/341512
They refer to this VMware KB http://kb.vmware.com/kb/1030265
In that KB there is the following note:
"Note: This issue only applies if you see this specific alert in the vmkernel/messages log files: ALERT: APIC: 1823: APICID 0x00000000 - ESR = 0x40. If you do not see this message, you are not experiencing this issue."
- We can't find that message (ALERT: APIC: 1823: APICID 0x00000000 - ESR = 0x40) in the vmkernel logs. Is this enough to state this KB does not apply?
- What is the impact if we DO apply the recommended solution on the ESXi 5.1 hosts?
Below is the vmkernel.log: