EFI labeled disk under OVM for SPARC (LDoms) environment

Asset ID:	1-72-1474271.1
Update Date:	2012-07-13
Keywords:

Solution Type Problem Resolution Sure

Solution 1474271.1 : EFI labeled disk under OVM for SPARC (LDoms) environment

Applies to:

Solaris SPARC Operating System - Version 10 10/09 U8 and later
Sun Fire T1000 Server - Version All Versions and later
Sun Fire T2000 Server - Version All Versions and later
Oracle Solaris on SPARC (64-bit)

Symptoms

These symptoms are some of the possible observations resulted from EFI labeled disk *not* being export through slice 2 on the primary domain ldm(1M) configuration. Do note that once you have confirmed that the vdisk configurations are correctly configured as outlined here, the following symptoms can be due to other issues.

My guest domain unable to find vdisk after primary domain reboot.
zpool on guest domain shown unavailable after guest/primary domain reboot.
Disk label observed to have changed, either on primary or guest domain.
The guest domain fails to boot due to missing boot disk.

Changes

Although /dev/dsk/cXtXd0 represents the entire disk for a disk with an EFI label, the problem with exporting /dev/dsk/cXtXd0 is that if the disk label is changed from EFI to VTOC (SMI) then this device will disappear. Resulting in various issues manifesting either on the primary or the guest domain.

Cause

EFI label has non overlapping slices and device cXtXd0 (e.g. c0t0d0) represents entire disk. It is common for one to assume that /dev/dsk/cXtXd00 would be the device for an entire disk export under OVM for SPARC.

On Solaris, when the disk is labeled as EFI, only then /dev/dsk/cXtXd0 exists. If the disk is re-labeled with SMI label, the cxtxd0 will be removed from the device path. Issue can arise when the disk is labeled EFI, cxtXd0 is configured as exported vdisk assigned to a guest domain. The guest domain subsequently re-labeled the disk as VTOC (SMI) for usage (e.g. a boot drive will need to be in VTOC (SMI) label). Upon reboot or any reconfiguration, the primary domain will now see the VTOC (SMI) label, with /dev/dsk/cXtXd0 no longer exists, and hence the disk is considered missing. The ldm(1M) configuration will no longer see /dev/dsk/cXtXd0, and the guest will now lost access to the the actual disk.

Solution

In order to export an entire disk under OVM for SPARC, slice 2(cXtXdXs2) needs to be the device path provided under ldm(1M) add-vdsdev, regardless of the underlying disk label format.

E.g.

format>
[0] SMI Label
[1] EFI Label
Specify Label type[0]: 1
Warning: This disk has an SMI label. Changing to EFI label will erase all
current partitions.
Continue? y

partition> p
Current partition table (default):
Total disk sectors available: 585921082 + 16384 (reserved sectors)

Part      Tag    Flag     First Sector         Size         Last Sector
0        usr    wm                34      279.39GB          585921082
1 unassigned    wm                 0           0               0
2 unassigned    wm                 0           0               0
3 unassigned    wm                 0           0               0
4 unassigned    wm                 0           0               0
5 unassigned    wm                 0           0               0
6 unassigned    wm                 0           0               0
7 unassigned    wm                 0           0               0
8   reserved    wm         585921083        8.00MB          585937466

# ls -l c0t5000CCA00AB5507Cd0*
lrwxrwxrwx   1 root     root          49 Jul 11 09:33 c0t5000CCA00AB5507Cd0 -> ../../devices/scsi_vhci/disk@g5000cca00ab5507c:wd
lrwxrwxrwx   1 root     root          48 Jun 18 12:03 c0t5000CCA00AB5507Cd0s0 -> ../../devices/scsi_vhci/disk@g5000cca00ab5507c:a
lrwxrwxrwx   1 root     root          48 Jun 18 12:03 c0t5000CCA00AB5507Cd0s1 -> ../../devices/scsi_vhci/disk@g5000cca00ab5507c:b
lrwxrwxrwx   1 root     root          48 Jun 18 12:03 c0t5000CCA00AB5507Cd0s2 -> ../../devices/scsi_vhci/disk@g5000cca00ab5507c:c
lrwxrwxrwx   1 root     root          48 Jun 18 12:03 c0t5000CCA00AB5507Cd0s3 -> ../../devices/scsi_vhci/disk@g5000cca00ab5507c:d
lrwxrwxrwx   1 root     root          48 Jun 18 12:03 c0t5000CCA00AB5507Cd0s4 -> ../../devices/scsi_vhci/disk@g5000cca00ab5507c:e
lrwxrwxrwx   1 root     root          48 Jun 18 12:03 c0t5000CCA00AB5507Cd0s5 -> ../../devices/scsi_vhci/disk@g5000cca00ab5507c:f
lrwxrwxrwx   1 root     root          48 Jun 18 12:03 c0t5000CCA00AB5507Cd0s6 -> ../../devices/scsi_vhci/disk@g5000cca00ab5507c:g

# ldm add-vdsvdev /dev/dsk/c0t5000CCA00AB5507Cd0s2 fulldisk4@primary-vds0
# ldm add-vdisk vdiks4 fulldisk4@primary-vds0 guestdomain1

With the introduction of device validation support in LDoms 2.1, ldm(1M) subcommand "add-vdsvdev" or "bind" may fail when assigning slice 2 due to the device validation. In order to workaround this, please use the -q option.

E.g.

# ldm add-vdsvdev -q /dev/dsk/c2t0d0s2 fulldisk4@primary-vds0

# ldm bind -q guestdomain1

INTERNAL ONLY REFERENCES

The underlying background on using slice 2 for EFI disk is disussed in the following CRs:

6423717 vds infers it is serving an entire disk by assuming use of the Solaris backup-slice convention
6679974 EFI labeled disk on primary domain is not properly accessible in guest domain.

References

<NOTE:1012091.1> - Overview of Extensible Firmware Interface (EFI) Disk Labels Versus Volume Table of Contents (VTOC) in the Solaris Operating System

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