Your customer want you to add a new volume in one of the VM SLES server but can not affort down time? No worry, you can do that easily with ESX.
Below is step by step guide with screen captured from the VM (my test machine is running on SLES10 SP2):
Tip: It is best to do a snapshot before you start this task, incase anything goes wrong.
1) This is my test VM machine. It is having one disk at beginning.
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Today, something weird happen. 1 of my VM guest which is windows 2003 server suddenly hung up. When I try to reset it, the Console screen show blank after the bios screen. I try to attach the VMDK to another newly created VM and it still not functioning. To verify the vmdk is not corrupted, I mount the vmdk to another windows 2003 VM and I found that the VMDK is functioning.
After that, I try to check most of the setting and log file from putty and virtual center. Here is my finding. Due to some unknown reason, the .vmx file setting and the configuration on the virtual center show really different. I had to force restart the virtual center service, and reconfigure some of the resources setting in virtual center to ensure it had not reserve or limit any resources on CPU and memory, and I power up the VM again. This round, the VM able to power up and functioning. Originally, It shouldn’t reserve any resource as I had not configured that. For some unknown reason, the resources limit had been configured by the ESX itself. This had happened in the pass but it had not cause any issue.
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Recently I had read a couple of article regarding the performance caparison chart from VMware, Netapps and some of the forum communities, I do really find out the real performance is much different with the technical white paper that I read before this.
As for the today, more users are actually deployed the mission critical and high I/O servers on the virtualization environment, but we do see some I/O bottle neck which cause by the storage performance always. VMDK do provide flexibility from management perspective, but it does sacrifice the performance you may require for your databases, files transfers and disk performance. I had run a couple of test with real case scenerio instead of I/O meter that been always use widely, and here is the summarize result I would like to share.
In disk perfomance, we always split it to 2 categories as sequential and random I/O. in sequential mode, you will see the huge different while you try to perform the file transfer locally or through network. My test environment is running with SAN storage from fiber channel with same LUN size and raid group which are created from the Storage Level. The only differences is VMFS Vs Raw.
Raid Group design 7+1 raid 5 configuration and run on MetaLun configuration
Each LUN size is 300GB
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