Template Volumes And Thin Clones - Dell EqualLogic PS6100 series Configuration Manual

•
A minimum physical allocation of 10% of the logical allocation is required
•
If a volume is converted to a thin provisioned volume, physical allocation cannot be less than
the amount of physical space already used within the volume
•
Any pool free space allocated to a thin provisioned volume is not returned to the free pool if
the host's file system usage of that volume is reduced (due to file system defragmentation,
data removal, etc.)
•
If a thin provisioned volume's allocated space exceeds the "maximum in-use space" setting,
the volume will go into an offline state.
•
Converting a volume to a thin provisioned volume may not reduce the physical allocation of
space the volume is using. Actual physical space recovered will depend on previous writing
patterns for the OS file system hosted on the volume.
•
All initial settings for "minimum volume reserve", "In-use volume reserve warning level" and
"maximum in-use space" are default recommendations and can be changed by the
administrator within the constraints defined above.
The following best practices should be considered when using thin provisioned volumes:
•
Use Pool Free Space, not Group Free Space when making all determinations of thin
provisioned volume physical capacity allocation.
•
Create regular volumes before creating thin provisioned volumes. This provides the
administrator with a better view of the remaining available free space in the pool.
•
Set each thin provisioned volume's "In use Volume Reserve Warning Level" to a level that
allows the administrator to ensure that additional physical storage can be deployed before the
volume uses the remainder of current pool free space.
•
Ensure that the Sum of all "In use Volume Reserve Warning Levels" for all thin provisioned
volumes does not exceed the current pool free space capacity minus 10%.
•
The storage administrator and application owner should reach an agreement on storage use
and procedures in determining the best automatic growth policy, reducing the frequency of
monitoring and intervention.
•
Be aware of the data usage patterns of the application. Some applications perform automated
disk optimization that may cause a thin provisioned volume to use more physical storage than
would be needed for normal operations. For these types of applications, thin provisioned
volumes may not be indicated.
•
Use "quick format" options when formatting OS file systems that are hosted by thin
provisioned volumes.
•
Thin provisioned volumes should not be used for hosting OS boot partitions or OS page file
cache.
5.4.1

Template volumes and thin clones

Template volumes and thin clones are new PS Series features introduced with firmware version 5.0.
Thin clones are created from template volumes. With a few exceptions, all normal volume operations
apply to template volumes and thin clones. For details on using template volumes and thin clones, see
Advanced volume operations  About template volumes and thin clones
the
Series Group Manager
March 2013
documentation.
Dell EqualLogic Configuration Guide v14.1
PS
section of the
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