Any Zettabyte File System (ZFS), Solaris Volume Manager (SVM), or Veritas Volume Manager (VxVM) volume can be exported from a service domain to a guest domain as a virtual disk. A volume can be exported either as a single slice disk (if the slice option is specified with the ldm add-vdsdev command) or as a full disk.
The remainder of this section uses an SVM volume as an example. However, the discussion also applies to ZFS and VxVM volumes.
The following examples show how to export a volume as a single slice disk.
The virtual disk in the guest domain (for example, /dev/dsk/c0d2s0) is directly mapped to the associated volume (for example, /dev/md/dsk/d0), and data stored onto the virtual disk from the guest domain are directly stored onto the associated volume with no extra metadata. So data stored on the virtual disk from the guest domain can also be directly accessed from the service domain through the associated volume.
Examples
If the SVM volume d0 is exported from the primary domain to domain1, then the configuration of domain1 requires some extra steps.
primary# metainit d0 3 1 c2t70d0s6 1 c2t80d0s6 1 c2t90d0s6 primary# ldm add-vdsdev options=slice /dev/md/dsk/d0 vol3@primary-vds0 primary# ldm add-vdisk vdisk3 vol3@primary-vds0 domain1 |
After domain1 has been bound and started, the exported volume appears as /dev/dsk/c0d2s0, for example, and you can use it.
domain1# newfs /dev/rdsk/c0d2s0 domain1# mount /dev/dsk/c0d2s0 /mnt domain1# echo test-domain1 > /mnt/file |
After domain1 has been stopped and unbound, data stored on the virtual disk from domain1 can be directly accessed from the primary domain through SVM volume d0.
primary# mount /dev/md/dsk/d0 /mnt primary# cat /mnt/file test-domain1 |
When a RAID or mirror SVM volume is used as a virtual disk by another domain, then it has to be exported without setting the exclusive (excl) option. Otherwise, if there is a failure on one of the components of the SVM volume, then the recovery of the SVM volume using the metareplace command or using a hot spare does not start. The metastat command sees the volume as resynchronizing, but the resynchronization does not progress.
For example, /dev/md/dsk/d0 is a RAID SVM volume exported as a virtual disk with the excl option to another domain, and d0 is configured with some hot-spare devices. If a component of d0 fails, SVM replaces the failing component with a hot spare and resynchronizes the SVM volume. However, the resynchronization does not start. The volume is reported as resynchronizing, but the resynchronization does not progress.
# metastat d0 d0: RAID State: Resyncing Hot spare pool: hsp000 Interlace: 32 blocks Size: 20097600 blocks (9.6 GB) Original device: Size: 20100992 blocks (9.6 GB) Device Start Block Dbase State Reloc c2t2d0s1 330 No Okay Yes c4t12d0s1 330 No Okay Yes /dev/dsk/c10t600C0FF0000000000015153295A4B100d0s1 330 No Resyncing Yes |
In such a situation, the domain using the SVM volume as a virtual disk has to be stopped and unbound to complete the resynchronization. Then the SVM volume can be resynchronized using the metasync command.
# metasync d0 |
When the Veritas Volume Manager (VxVM) is installed on your system, and if Veritas Dynamic Multipathing (DMP) is enabled on a physical disk or partition you want to export as virtual disk, then you have to export that disk or partition without setting the (non-default) excl option. Otherwise, you receive an error in /var/adm/messages while binding a domain that uses such a disk.
vd_setup_vd(): ldi_open_by_name(/dev/dsk/c4t12d0s2) = errno 16 vds_add_vd(): Failed to add vdisk ID 0 |
You can check if Veritas DMP is enabled by checking multipathing information in the output of the command vxdisk list; for example:
# vxdisk list Disk_3 Device: Disk_3 devicetag: Disk_3 type: auto info: format=none flags: online ready private autoconfig invalid pubpaths: block=/dev/vx/dmp/Disk_3s2 char=/dev/vx/rdmp/Disk_3s2 guid: - udid: SEAGATE%5FST336753LSUN36G%5FDISKS%5F3032333948303144304E0000 site: - Multipathing information: numpaths: 1 c4t12d0s2 state=enabled |
Alternatively, if Veritas DMP is enabled on a disk or a slice that you want to export as a virtual disk with the excl option set, then you can disable DMP using the vxdmpadm command. For example:
# vxdmpadm -f disable path=/dev/dsk/c4t12d0s2 |