Open Stack

Hi Daniel,

     Thanks for your comments about this BP：https://review.openstack.org/#/c/83727/
 
     My initial thoughts is to do little changes then get better performance of guest vm. So it is a bit too narrowly focused.

     After review SSD use case, I totally agree with your comments. I think if I want to implement the broader picture, there are many work items that need to do.

1. Add support to create flavor with SSD ephemeral storage.
     The cloud adminstrator create the flavor that indicate which backend should be used per instance. e.g.        
          nova flavor-key m1.ssd set quota:ephemeral_storage_type=ssd 
		 	(root_disk ephemeral_disk and swap_disk are placed onto a ssd)
     Or more fine grained, e.g.
          nova flavor-key m1.ssd set quota:root_disk_type=ssd
          nova flavor-key m1.ssd set quota:ephemeral_disk_type=hd
          nova flavor-key m1.ssd set quota:swap_disk_type=ssd
			(root_disk and swap_disk are placed onto a ssd, ephemeral_disk is placed onto a harddisk)

2. When config nova,the deployer of openstack configure <ephemeral_storage_pools>
e.g.
     if libvirt_image_type=default (local disk)
          ephemeral_storage_pools=<path1>,<path2> 
     if  libvirt_image_type=RBD
           ephemeral_storage_pools=rdb1,rdb2

3. According to  ephemeral storage type in compute host, nova-scheduler select compute node to create VM.

4. Assume  that ssd mount on <path1> ,hd mount on <path2>, and assume that the end user select the flavor with ssd ephemeral storage, when creating VM,  nova-compute place root_disk/ephemeral_disk /swap_disk onto <path1>.

 	My description about  broader picture  is right or not?

	Welcome for your more comments!

Thanks.

Zhou Yu