Volume Manager support for devices larger than 1 TB on Solaris platform

Problem

Volume Manager support for devices larger than 1 TB on Solaris platform

Solution

Volume Manager (VxVM) support for devices larger than 1 TB on Solaris platform depends on the underlying Operating System device Label and version.

Volume Manager does not support the use of a SUN Solaris Sun Microsystems Inc. (SMI) label on devices larger than 1 TB. Veritas Volume Manager does support devices larger than 1 TB, but only by using an Extensible Firmware Interface GUID Partition Table (EFI GPT) label on devices larger than 1 TB.

Volume Manager cannot address more than 1 TB space on a single device with an SMI label because VxVM uses Volume Table Of Contents commonly known as VTOC (SMI) label to calculate the disk geometry. The slice or partition values are declared at the Operating System level as "signed int i.e. 32 bit" and hence the maximum number of sectors in a slice or partition in Solaris VTOC (SMI label) can be 2^31 since since 1 bit is reserved for sign, -/+. 

Hence we have:

2 ^ 31   =   2147483648 blocks    =    1 TB

This is the reason why we can have the maximum size of a single slice in Solaris of 1 TB; therefore limiting the supported size of a device with a SMI label to be restricted to 1 TB in size to be used in Volume Manager. 

For further detailed information regarding the differences between the SMI and EFI labels,  how to change between the two label types on devices in Solaris and about the support restrictions on devices larger than 1 TB in size, customers may contact the Operating System Vendor for exact details.

Veritas statement on Volume Manager (VxVM) support for devices larger than 1 TB:

• Volume Manager does not support the use of a SUN Solaris Sun Microsystems Inc. (SMI) label on devices larger than 1 TB. Veritas Volume Manager does support devices larger than 1 TB, but only by using an Extensible Firmware Interface GUID Partition Table (EFI GPT) label on devices larger than 1 TB
• At the time of writing this document, the Solaris Operating System does not support the boot devices to be larger than 1 TB and hence Volume Manager cannot support boot devices larger than 1 TB
• Volume Manager supports EFI disks on Solaris 10 only.
• Volume Manager supports devices larger than 1 TB prior to the version of Storage Foundation 5.1 SP1. However, prior to version of Storage Foundation 5.1 SP1, devices larger than 1 TB requires us to use the Volume Manager initialization type as "sliced" or "simple" format. Note that the default initialization format in Volume Manager is of "cdsdisk" format and hence, to use such devices larger than 1 TB in Volume Manager control requires the devices to be explicitly initialized in "simple" or "sliced" format. This can be achieved by using the 'vxdisksetup' command or by using the 'vxdiskadm' Command Line Interface (CLI) utility.
• Veritas has introduced the support for devices larger than 1 TB with an EFI GPT label to be initialized in "cdsdisk" format starting from the version of Storage Foundation 5.1 SP1 onwards; hence there is no longer a restriction to initialize such devices in "simple" or "sliced" format as it was required in earlier versions.