Veritas Volume Manager (VxVM) incorrectly initializes over-1TB EFI LUNs as CDS disks

Article:TECH138372  |  Created: 2010-08-24  |  Updated: 2013-01-03  |  Article URL http://www.symantec.com/docs/TECH138372
Article Type
Technical Solution

Product(s)

Environment

Issue



Veritas Volume Manager (VxVM) incorrectly initializes over-1TB EFI LUNs as CDS disks


Error



# vxdisk list emc_clariion0_5
.....
info:      format=cdsdisk,privoffset=256,pubslice=3,privslice=3    <<< CDS disk
.....
public:    slice=3 offset=65792 len=2516434688 disk_offset=0    <<< bigger than 1TB
private:   slice=3 offset=256 len=65536 disk_offset=0
.....

 


Cause



Before VxVM 5.1SP1 is released, Cross-Platform Sharing (CDS) Disk has a size limitation of 1TB.    The 1TB limitation is required for the successful migration of the VxVM disk across platforms (on Solaris the Sun SMI Disk Label has a limitation of 1TB).   But due to Etrack 1630572, disks with greater than 1TB size were allowed to be initialized as CDS disk on Linux.   The following is an example of an incorrectly initialized CDS disk.

# vxdisk list emc_clariion0_5
.....
info:      format=cdsdisk,privoffset=256,pubslice=3,privslice=3    <<< CDS disk
.....
public:    slice=3 offset=65792 len=2516434688 disk_offset=0    <<< bigger than 1TB
private:   slice=3 offset=256 len=65536 disk_offset=0
.....

# fdisk -l /dev/sdv
Disk /dev/sdv (Sun disk label): 256 heads, 160 sectors, 61438 cylinders
Units = cylinders of 40960 * 512 bytes
  Device Flag    Start       End    Blocks   Id  System
/dev/sdv3  u          0     61438 1258250240    5  Whole disk
/dev/sdv8  u          0     61438 1258250240    f  Unknown

Etrack 1630572 was  fixed in Linux VxVM 5.0MP3RP3HF2.   After applying 5.0MP3RP3 HF2 VxVM will no longer allow CDS disks to be initialized larger than 1TB, both the CDS disk public region and the disk partition table entries will be limited to 1TB.   Please note that applying VxVM 5.0MP3RP3HF2 will not affect the I/O access of the incorrectly initialized CDS disks.  On Linux the Sun Label is ignored and the LUN size is determined through /proc/partitions.  

In VxVM  5.1SP1 there will be a new VxVM disk type which allows CDS disk to be created on an EFI LUN.   With VxVM SF 5.1SP1 if an CDS disk is detected on an EFI LUN, that disk will be converted automatically to the new format.   The new CDS/EFI disk will have size limited to 2TB.


Solution



If cross-platform capability is required, please apply Linux VxVM 5.0MP3RP3 HF2 or later to limit the size of CDS disk to 1TB.

If CDS disk with size up to 2TB is required, please apply the up-coming Linux VxVM 5.1 SP1.

 


Supplemental Materials

SourceETrack
Value1630572
Description

Creating cdsdisk layout on GPT-labeled disks on Linux platform is defective


SourceETrack
Value2034898
Description

Allow Linux to create and import cdsdisks of size more than 1 TB


SourceETrack
Value2021737
Description

HDS TrueCopy S-VOL type devices displayed as "error" in vxdisk list whilst read-only (for some production versions and platforms, the fix for Etrack 2034898 is incorporated in the fix for this etrack)



Article URL http://www.symantec.com/docs/TECH138372


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