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Oracle VM Server for SPARC 2.0 Administration Guide |
1. Overview of the Oracle VM Server for SPARC Software
2. Installing and Enabling Software
4. Setting Up Services and the Control Domain
Export a Virtual Disk Back End Multiple Times
Virtual Disk Identifier and Device Name
Export a Physical Disk as a Virtual Disk
Export a Physical Disk Slice as a Virtual Disk
File or Volume Exported as a Full Disk
File or Volume Exported as a Single-Slice Disk
Export a ZFS Volume as a Single-Slice Disk
Exporting Volumes and Backward Compatibility
Summary of How Different Types of Back Ends Are Exported
Guidelines for Exporting Files and Disk Slices as Virtual Disks
Using the Loopback File (lofi) Driver
Directly or Indirectly Exporting a Disk Slice
Configuring Virtual Disk Multipathing
Configure Virtual Disk Multipathing
Export a CD or DVD From the Service Domain to the Guest Domain
Export an ISO Image From the primary Domain to Install a Guest Domain
Virtual Disk and the format(1M) Command
Configuring a ZFS Pool in a Service Domain
Examples of Storing Disk Images With ZFS
Create a Disk Image Using a ZFS Volume
Create a Disk Image Using a ZFS File
Assign the ZFS Volume or File to a Guest Domain
Creating a Snapshot of a Disk Image
Create a Snapshot of a Disk Image
Using Clone to Provision a New Domain
Using Volume Managers in a Logical Domains Environment
Using Virtual Disks on Top of Volume Managers
Using Virtual Disks on Top of Solaris Volume Manager
Using Virtual Disks When VxVM Is Installed
Using Volume Managers on Top of Virtual Disks
Using ZFS on Top of Virtual Disks
Using Solaris Volume Manager on Top of Virtual Disks
Using VxVM on Top of Virtual Disks
12. Performing Other Administration Tasks
A. Oracle VM Server for SPARC Physical-to-Virtual Conversion Tool
B. Oracle VM Server for SPARC Configuration Assistant
C. Logical Domains Manager Discovery
D. Using the XML Interface With the Logical Domains Manager
Different options can be specified when exporting a virtual disk back end. These options are indicated in the options= argument of the ldm add-vdsdev command as a comma separated list. The valid options are: ro, slice, and excl.
The read-only (ro) option specifies that the back end is to be exported as a read-only device. In that case, the virtual disk assigned to the guest domain can only be accessed for read operations, and any write operation to the virtual disk will fail.
The exclusive (excl) option specifies that the back end in the service domain has to be opened exclusively by the virtual disk server when it is exported as a virtual disk to another domain. When a back end is opened exclusively, it is not accessible by other applications in the service domain. This prevents the applications running in the service domain from inadvertently using a back end that is also being used by a guest domain.
Note - Some drivers do not honor the excl option and will disallow some virtual disk back ends from being opened exclusively. The excl option is known to work with physical disks and slices, but the option does not work with files. It may or may not work with pseudo devices, such as disk volumes. If the driver of the back end does not honor the exclusive open, the back end excl option is ignored, and the back end is not opened exclusively.
Because the excl option prevents applications running in the service domain from accessing a back end exported to a guest domain, do not set the excl option in the following situations:
When guest domains are running, if you want to be able to use commands such as format(1M) or luxadm(1M) to manage physical disks, then do not export these disks with the excl option.
When you export an Solaris Volume Manager volume, such as a RAID or a mirrored volume, do not set the excl option. Otherwise, this can prevent Solaris Volume Manager from starting some recovery operation in case a component of the RAID or mirrored volume fails. See Using Virtual Disks on Top of Solaris Volume Manager for more information.
If the Veritas Volume Manager (VxVM) is installed in the service domain and Veritas Dynamic Multipathing (VxDMP) is enabled for physical disks, then physical disks have to be exported without the (non-default) excl option. Otherwise, the export fails, because the virtual disk server (vds) is unable to open the physical disk device. See Using Virtual Disks When VxVM Is Installed for more information.
If you are exporting the same virtual disk back end multiple times from the same virtual disk service, see Export a Virtual Disk Back End Multiple Times for more information.
By default, the back end is opened non-exclusively. That way the back end still can be used by applications running in the service domain while it is exported to another domain. Note that this is a new behavior starting with the Oracle Solaris 10 5/08 OS release. Prior to the Oracle Solaris 10 5/08 OS release, disk back ends were always opened exclusively, and it was not possible to have a back end opened non-exclusively.
A back end is normally exported either as a full disk or as a single-slice disk depending on its type. If the slice option is specified, then the back end is forcibly exported as a single-slice disk.
This option is useful when you want to export the raw content of a back end. For example, if you have a ZFS or Solaris Volume Manager volume where you have already stored data and you want your guest domain to access this data, then you should export the ZFS or Solaris Volume Manager volume using the slice option.
For more information about this option, see Virtual Disk Back End.
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