EFI Disk Label

The EFI label provides support for physical disks and virtual disk volumes that are greater than 2 TB in size. This release also includes updated disk utilities for managing disks greater than 2 TB in size. The UFS file system is compatible with the EFI disk label, and you can create a UFS file system greater than 2 TB. For information on creating a multiterabyte UFS file system, see .

The unbundled Sun QFS file system is also available if you need to create file systems greater than 1 TB. For information on the Sun QFS file system, see .

The Solaris Volume Manager software can also be used to manage disks greater than 1 TB in this Solaris release. For information on using Solaris Volume Manager, see .

The VTOC label is still available for disks less than 2 terabytes in size. If you are only using disks smaller than 2 TB on your systems, managing disks will be the same as in previous Solaris releases. In addition, you can use the format-e command to label a disk 2 TB in size or less with an EFI label. For more information, see .

You can use the format -e command to apply an EFI label to a disk if the system is running the appropriate Solaris release. However, you should review the important information in before attempting to apply an EFI label.

You can also use the format -e command to reapply a VTOC label if the EFI label is no longer needed. For example:

# format
Specify disk (enter its number): 2
selecting c0t5d0
[disk formatted]
.
.
.
format> label
[0] SMI Label
[1] EFI Label
Specify Label type[1]: 0
Warning: This disk has an EFI label. Changing to SMI label will erase all
current partitions.
Continue? yes
Auto configuration via format.dat[no]? 
Auto configuration via generic SCSI-2[no]? 
format> quit

Caution –

Keep in mind that changing disk labels will destroy any data on the disk.

Comparison of the EFI Label and the VTOC Label

The EFI disk label differs from the VTOC disk label in the following ways:

Provides support for disks greater than 2 terabytes in size.
Provides usable slices 0-6, where slice 2 is just another slice.
Partitions (or slices) cannot overlap with the primary or backup label, nor with any other partitions. The size of the EFI label is usually 34 sectors, so partitions usually start at sector 34. This feature means that no partition can start at sector zero (0).
No cylinder, head, or sector information is stored in the EFI label. Sizes are reported in blocks.
Information that was stored in the alternate cylinders area, the last two cylinders of the disk, is now stored in slice 8.
If you use the format utility to change partition sizes, the unassigned partition tag is assigned to partitions with sizes equal to zero. By default, the format utility assigns the usr partition tag to any partition with a size greater than zero. You can use the partition change menu to reassign partition tags after the partitions are changed. However, you cannot change a partition with a non-zero size to theunassigned partition tag.

Restrictions of the EFI Disk Label

Keep the following restrictions in mind when determining whether using disks greater than 1 terabyte is appropriate for your environment:

Layered software products intended for systems with VTOC-labeled disks might be incapable of accessing a disk with an EFI disk label.
A disk with an EFI label is not recognized on systems running previous Solaris releases.
You cannot boot from a disk with an EFI disk label.
On x86-based systems, you can use the fdisk command on a disk with an EFI label that is greater than 2 TB in size.
You cannot use the Solaris Management Console's Disk Manager tool to manage disks with EFI labels. Use the format utility to partition disks with EFI labels. Then, you can use the Solaris Management Console's Enhanced Storage Tool to manage volumes and disk sets with EFI-labeled disks.
The EFI specification prohibits overlapping slices. The entire disk is represented by cxtydz.
The EFI disk label provides information about disk or partition sizes in sectors and blocks, but not in cylinders and heads.
The following format options are either not supported or are not applicable on disks with EFI labels:
- The save option is not supported because disks with EFI labels do not need an entry in the format.dat file.
- The backup option is not applicable because the disk driver finds the primary label and writes it back to the disk.

Support for EFI-Labeled Disks on x86 Systems

Solaris support for the EFI disk label is available on x86 systems. Use the following command to add an EFI label on an x86 system:

# format -e > [0] SMI Label
> [1] EFI Label
> Specify Label type[0]: 1 > WARNING: converting this device to EFI labels will erase all current
> fdisk partition information. Continue? yes

Previous label information is not converted to the EFI disk label.

You will have to recreate the label's partition information manually with the format command. You cannot use the fdisk command on a disk with an EFI label that is 2 terabytes in size. If the fdisk command is run on disk that is greater than 2 TB in size to create a Solaris partition, the Solaris partition is limited to 2 TB. For more information about EFI disk labels, see the preceding section.

Installing a System With an EFI-Labeled Disk

The Solaris installation utilities automatically recognize disks with EFI labels. However, you cannot use the Solaris installation program to repartition these disks. You must use the format utility to repartition an EFI-labeled disk before or after installation. The Solaris Upgrade and Live Upgrade utilities also recognize a disk with an EFI label. However, you cannot boot a system from an EFI-labeled disk.

After the Solaris release is installed on a system with an EFI-labeled disk, the partition table appears similar to the following:

Current partition table (original):
Total disk sectors available: 2576924638 + 16384 (reserved sectors)

Part      Tag    Flag     First Sector          Size          Last Sector
  0       root    wm                34         1.20TB           2576924636
  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    
  8   reserved    wm        2576924638         8.00MB           2576941021

Managing Disks With EFI Disks Labels

Use the following table to locate information on managing disks with EFI disk labels.

Task	For More Information
If the system is already installed, connect the disk to the system and perform a reconfiguration boot.	or
Repartition the disk by using the format utility, if necessary.	or
Create disk volumes, and if needed, create soft partitions by using Solaris Volume Manager. Or, set up a ZFS storage pool.	or
Create UFS file systems for the new disk by using thenewfs command.	or
Or, create a ZFS file system.
Clone a disk with an EFI label

Troubleshooting Problems With EFI Disk Labels

Use the following error messages and solutions to troubleshoot problems with EFI-labeled disks.

Error Message

Dec  3 09:26:48 holoship scsi: WARNING: /sbus@a,0/SUNW,socal@d,10000/
sf@1,0/ssd@w50020f23000002a4,0 (ssd1):
Dec  3 09:26:48 holoship disk has 2576941056 blocks, which is too large 
for a 32-bit kernel

Cause

You attempted to boot a system running a 32-bit SPARC or x86 kernel with a disk greater than 1 terabyte.

Solution

Boot a system running a 64-bit SPARC or x86 kernel with a disk greater than 1 terabyte.