Thank you very much. It's clear now. One more question, I see that the API of the free ESX 3i version only support read-only operations like monitoring. When I firstly installed ESXi and didn't use the free license, I have 60 days' evaluation and VCL could successfully do all operations. But when I used the free license, some features were removed and VCL could not register VM correctly.
Does it mean we should always use evaluation mode to support VCL's operation? 2009/5/6 Brian Bouterse <bmbou...@ncsu.edu> > Regarding NFS, below are a few practical reasons to not use local hard > disks to host the images as they run. > > 1) Say each image is 10GB, on a 72GB hard drive (the standard "large" > drive in a blade), that means as a maximum consolidation you can only have 7 > VM's on a blade. A blade can likely handle between 4 - 30 VMs depending on > how powerful it is, so this would be a gross underutilization. > > 2) It takes a VERY long time to copy images to and from the blades (3-6 > MB/s) because of the difficult file system translation between to and from > the VMFS filesystem format on the hypervisor. > > 3) ESX 3i (the free, efficient hypervisor) is designed to boot as a > disksless hypervisor, so ESX3i environments would be out which would reduce > the number of folks who could do this dramaticlly > > 4) Although it seems performance counter-intuative, actually if booting > from an actual storage system with multiple disks, VMs will perform quicker > when booting over the network. Consider the HD thrashing that would occur > if a single disk were really handling the I/O operations of 20VMs on a > single hypervisor. Believe it or not, the network is faster. > > 5) While not possible with VCL today, if the instance images live on the > network natively, the opportunity to do things like Vmotion aren't totally > out of the question, but those are not at all possible with local disk boot. > > In regards to image re-using, your configuration is not correct. It sounds > like you need to create a few more computer "slot" entries in the computer > table and link those slots to your hypervisor entry in the computer table. > The number of "slots" you have equals the number of virtual machines that > can run concurrently. Notice it actually copies it from > /golden/<image_name>/ to /inuse/<slot_name>. Once a slot is created, > remember to associate it with a hypervisor through the "Virtual Hosts" area. > If you still can't get this, post up some of the lines in your computer > table's DB. > > Best, > Brian > > Brian Bouterse > Secure Open Systems Initiative > 919.698.8796 > > > > > > On May 6, 2009, at 2:07 AM, 乔木 wrote: > > Hi, >> >> We have setup the environment for VM provision on ESXi recently. We are >> confused about some mechanisms: >> >> - Images are stored in NFS >> >> As I see, VCL stores images in NFS and just copy it locally when using it. >> It means that the hardisk in the esxi hypervisor will not be used. All the >> VMs are stored in remote computer and all the operations will be remote >> operation (CPU exsits in Hypervisor but hardisk exsits in NFS). I think it >> may lead performance problems. Although we can setup mutiple NFS servers, >> it >> is not good that the hardisk in the hypervisor is not used and all the >> operations will be remote in my opinion. Why not transfer the image to the >> esxi hypervisor which will run the image? >> >> - Image reusing >> >> When we use an image from repository, VCL does: 1. copy the image form >> /golden/<image_name> to /inuse/<image_name>, 2. start the image. It's >> difficult for image reusing. It's impossible for mutiple machines to use >> the >> same image because the copy operation will only copy one image to the >> /inuse >> folder and that image can be used only for one esxi hypervisor. Other copy >> operation will overwrite that image. Again, if we transfer the image to >> hypervisor, there won't be such problem. >> >> >> -- >> Best wishes, >> 乔木 >> MOE KLINNS Lab and SKLMS Lab, Xi'an Jiaotong University >> Department of Computer Science and Technology, Xi’an Jiaotong University >> TEL: 15991676983 >> E-mail: qiao...@gmail.com >> > > -- Best wishes, 乔木 MOE KLINNS Lab and SKLMS Lab, Xi'an Jiaotong University Department of Computer Science and Technology, Xi’an Jiaotong University TEL: 15991676983 E-mail: qiao...@gmail.com