“You’re a daisy if you do.”
IBM x3850 eServers with 26GB of RAM in each and XenServer 5.5 w/ two qlogic fibre channel HBAs hooked to 2 – Cisco MDS9124 fabric switches in a fully redundant environment. Sounds too good to be true and is was. Until tonight.
Started experiencing slowness on several of the servers while booting a VM or shutting down or migrating. They would take about 14 minutes to POST and boot into windows. Also when checking the status of the DS4300 the LUN assigned to the xenservers was thrashing between controller a and controller b. I started out by finding an article on crossnet.com that matched to the ‘T’ what I was experiencing. It had everything to do with the multipath drivers for the qlogic HBAs i am using in my xenserver hosts. The difference between the dmp and the mpp drivers and some instructions for changing the driver from dmp to mpp can be found on Citrix knowledgeBase article here. Several hours later I felt I was on the right track but below are some of the sites and procedures that fixed my problem. I will post the scripts and instructions very soon.