![]() So now we got the basic Idea about the Ephemeral disks. Then use virsh domblklist to see attachments: _base]# virsh domblklist instance-00000012 by virsh list get the list of instances running on a Compute Node _base]# virsh list If you are using KVM on OpenStack you can see the devices actually attached to your instance with the virsh domblklist command. You can verify the same with command “qemu-img info “ _base]# qemu-img info /var/lib/nova/instances/d49cb9b8-6b95-40f4-aa77-6dbb2eb701c1/disk.eph0 The Image under /var/lib/nova/instances/_baseis used as a backing file for all Instances booted with that image. This allows very large disks to be provisioned very fast once the image has been downloaded to the compute node, and this means that the image only needs to be downloaded once per compute node rather than once per instance. Why because at the very first time an image is used on a compute node that image is fetched from Glance into the /var/lib/nova/instances/_base directory. You will notice in above output that the size of the Ephemeral disk is very less not even equal to the image size as I am using cirros image here expected to be sized about 12 Mb. ![]() When you Launch a new Instance with the flavor given Ephemeral storage it use the path /var/lib/nova/instances/ for qcow2 image. but again its Optional to use Ephemeral storage, if you do not use Ephemeral storage the boot files fill be saved under Persistence storage. That is the only main difference between Ephemeral and persistence Storage.īoth types of storage can be exist on the local system or on external storage.īasically Ephemeral storage used to store the Image boot files. Other side Persistence storage are not deleted even the VM is terminated but you need to specify it during Instance creation. ![]() In this topic we will discuss about the Ephemeral storage and Persistence storage used in Openstack.Įphemeral storage are not persistence yes because once you terminate the instance the Storage will be deleted.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |