|
|
|
|
|
The disk group block alignment has two values: 1 block or 8k (8 kilobytes).
All disk group versions before version 110 must have an alignment value of 1.
Note
Disk groups with version numbers less than 110 are not supported for the Solaris OS on the x64 platform.
Disk groups have an alignment value of 1 after upgrading from pre-version 110 to version 110 or later.
Encapsulated disks, which require disk cylinder alignment, have an alignment value of 1.
Non-CDS disk groups version 110 and later can have either a value of 1 block or 8k.
Non-CDS disk groups version 110 and later can have either a value of 1 block or 8k.
All CDS disk groups have an alignment value of 8k.
The alignment for all newly initialized disk groups in VxVM 4.0 or a later release is 8k. This value (which is used when creating the disk group) cannot be changed. However, the disk group alignment can be subsequently changed.
See "Changing the alignment of a non-CDS disk group" on page 29.
Note
The default usage of vxassist is to set the layout=diskalign attribute on all platforms. The layout attribute is ignored on 8K-aligned disk groups, which means that scripts relying on the default may fail.
The location and size of each map within a dirty region log (DRL) must not violate the disk group alignment for the disk group (containing the volume to which the DRL is associated). This means that the region size and alignment of each DRL map must be a multiple of the disk group alignment, which for CDS disk groups is 8K. (Features utilizing the region size can impose additional minimums and size increments over and above this restriction, but cannot violate it.)
In a version 110 disk group, a traditional DRL volume has the following region requirements:
In a version 110 disk group, a version 20 DCO volume has the following region requirements:
Note
The map layout within a Data Change Object (DCO) volume changed with the release of VxVM 4.0 to version 20. This can accommodate both FastResync and DRL maps within the DCO volume. The original version 0 layout for DCO volumes only accommodates FastResync maps.