Saturday, October 11, 2008

Oracle VM ovs-makerepo

When you want to use of a remote storage solution in Oracle VM and you would like to use it for your virtual machines you will have to setup Oracle VM Server Repository for your storage. You can also make remote storage available bye editing your /etc/fstab file, however the correct way is to use the ovs-makerepo tool provided by oracle.

The reasons you would like to store virtual machines on a remote storage can be that you would like to use the live migration option and/or you just want things nice and tidy on a remote storage so you can easily backup and snapshot things. This way you do no longer need a lot of diskspace in your hardware server, you just have a large pool of diskspace where you can reserve a part for a operating system.

You can find the ovs-makerepo tool in /usr/lib/ovs.

[root@oebs11 ovs]# ./ovs-makerepo
usage: ./ovs-makerepo
source: block device or nfs path to filesystem
shared: filesystem shared between hosts? 1 or 0, or @ or C for cluster root (/OVS)
description: descriptive text to be displayed in manager
[root@oebs11 ovs]#

To create a repository you have to provide a source where you tell the system where the storage is located, you have to tell if it can be shared by different hosts and you can give a short meaningful description. For example the following command:

[root@oebs11 ovs]# ./ovs-makerepo 10.73.69.199:/vol/uat/virt_storage_0 1 VIRTUAL_DISK_0

If you now check the mounts on your system with a 'df -h' you will see a new mount in your /OVS directory with a large random name. This is your new repository. instead of making use of /etc/fstab Oracle VM will make use of the /etc/ovs/repositories file to setup the mounts. The listing in /etc/ovs/repositories is quite basic. You might want to use some more options on how your repository is mounted to the server. You can do this by editing the file /etc/ovs/repositories.options. The format of this file is: uuid options. The uuid parameter is the UUID (Universally Unique Identifier) of the repository and must match the UUID of the repository in the /etc/ovs/repositories file. The options parameter is list of mount options, as they would appear if the volume were mounted with mount -o opt1,opt2,opt3. The mount options will be used exactly as listed in the file until the end of the line.

If you want to remove a repository for some reason you can do so by issuing a ovs-offlinerepo command. This tool can be found also in /usr/lib/ovs . ovs-offlinerepo will umount the repository and remove the automount instructions from the system. issue: ovs-offlinerepo [-d] uuid source where uuid is the ID of the repository and source is the source location (the filer) where you mounted on.


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