FS System: Limit LUN to Requested Capacity

Asset ID:	1-72-2242028.1
Update Date:	2017-03-10
Keywords:

Solution Type Problem Resolution Sure

Solution 2242028.1 : FS System: Limit LUN to Requested Capacity

Applies to:

Oracle FS1-2 Flash Storage System - Version All Versions to All Versions [Release All Releases]
Pillar Axiom Replication Engine (MaxRep) - Version 3.0 to 3.0 [Release 3.0]
Information in this document applies to any platform.

Symptoms

Replication pairs are unable to replicate because sizes do not match exactly.

Changes

This is a new feature implemented with FS1-2 software version R6.2.11 and is useful for when configuring a replication pair.

Cause

Rounding may not result in the exact physical space being different on source and destination FS1s. This will prevent replication.

Solution

With the release of R6.2.11 the option to Limit LUN to Requested Capacity is available for both auto-tier and single-tier LUNs. This value will set the capacity as exposed to SAN hosts, for the purpose of creating LUNs that are the same size as viewed by hosts.

It specifies that the amount of storage is limited to the amount of space set by the Capacity option. If you do not use the Limit LUN to Requested Capacity option, the amount of space used by the volume might be rounded up to an allocation segment boundary, resulting in a LUN that is larger than requested. Use this option when strict control over the LUN capacity is required, such as configuring a replication pair.

In the GUI select SAN tab --> Storage --> LUNs, Actions -->Create. Then select Additional Options and check the "Limit LUN to Requested Capacity" option:

Additional Options Window

Oracle FS1-2 Flash Storage System Release Notes, Release 6.2.11

References

<BUG:25294088> - LUN OVERHEAD MISMATCH BETWEEN FS1-2
<BUG:22513799> - PLEASE ADD ABILITY TO DEFINE HOST-EXPOSED LUN CAPACITY TO GUI

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