Thursday, January 21, 2016

SMI and EFI disk label on Solaris

SMI:     SMI – Sun Microsystem Inc Label

1.       Typically, SPARC based Solaris based file system.
   SPARC VTOC is often called as SMI VTOC.
2.       Can define 8 partitions (0-7).
3.       Provides support to < 1Tb.
4.       Occupies first sector of a disk in SPARC arch systems.
5.       Must be used for SPARC, X86/X64 based boot disks.
6.       Maintains 2 partition tables on each disk on X86/X64.
(a)    First sector : Contains fixed disk (fdisk) partition table
(b)   Second sector: Holds the partition table that defines slices in the Solaris ‘fdisk’ partition.

EFI:   EFI – Extensible Firmware interface

1.       Can define up to 10 disk partitions (0-9).
2.       Supports > 1 Tb on 64-bit Solaris kernel.
3.       Compatible with UFS and can create a UFS that is larger than 1Tb.
4.       Do not currently boot from disk that use EFI label on Solaris 10.
Solaris 11 support boot disk with EFI (GPT) label.
SPARC systems require an updated OBP to boot from an EFI (GPT) labeled disk.
X86 systems that supports GRUB 2 boots from an EFI (GPT) labeled disk.
5.       Provide usable slices 0-6, where slice 2 is just another slice.
6.       Slices cannot overlap with the primary or backup labels or with other partition.
7.       No cylinder, head or sector information is stored in the EFI label.
8.       Sizes are reported in blocks.
9.       EFI labeled information that is stored in alternate cylinder areas (last 2 disk       cylinder) is stored in slice 8.
10.   On EFI, slice 2 can be resized.
11.   EFI label size is usually 34 sectors, so partitions start at sector 34. This feature   means that no partition can start at sector 0.
12.   EFI does not support  -
At ‘format’ utility -
(a)    save’ is not supported. Because EFI labeled disks do not need a   format.dat file entry.
(b)   backup’ is not applicable. Because the disk driver finds the primary        label and write it back to the disk.