Asset ID:	1-71-1003849.1
Update Date:	2009-12-20
Keywords:

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Solution Type  Technical Instruction Sure

Solution  1003849.1 :   Number of LDEVs in TrueCopy Consistency Groups Should be Limited  


PreviouslyPublishedAs
205404

Description
Membership in TrueCopy Consistency Groups should be limited in order to avoid a performance degradation.


Steps to Follow
When writing to a TrueCopy Primary Volume (PVOL), a write to a single volume causes an update to all volumes in the consistency group in which the PVOL resides. This can potentially create a great deal of contention, and may result in a significant performance degradation on hosts attached to the Master Control Unit (MCU) array.

Therefore, when creating consistency groups, restrict the logical devices (LDEVs) making up the group to a small number of logically related volumes. For example, instead of putting all replicated LDEVs in a single group, consider using a separate group for the replicated LDEVs in a particular parity group, or a similar logical grouping. There is no rule for determining an ideal ratio of LDEVs to groups. To some extent this ratio must be dictated by the size of the LDEVs and the number of replicated LDEVs. However, it is highly recommended to keep the consistency groups relatively small, and to put logically related LDEVs into common groups.

Product
Sun StorageTek 9990 System
Sun StorageTek 9980 System
Sun StorageTek 9970 System
Sun StorageTek 9960 System
Sun StorageTek 9910
Sun StorageTek 9900V Series Array
Network Storage

TrueCopy, performance, consistency, LDEV
Previously Published As
81877

Change History
Date: 2007-05-25
User Name: 31620
Action: Modify Tech Group
Comment: Moving to storage to ensure IBIS migration takes it over to Oracle
Andy - Admin Modify of Tech Group to Storage
Version: 0
Date: 2005-06-17
User Name: 7058
Action: Approved
Comment: Acronyms expanded.
Publishing.
Version: 4
Date: 2005-06-15
User Name: 107670
Action: Approved
Comment: Hi Nita,
Requested changes have been made.
Regards,
Charlie
Version: 0
Product_uuid
15644879-f179-11d8-ab63-080020a9ed93|Sun StorageTek 9990 System
c2428fbe-8ab7-41d0-8b6e-ab489823c9d4|Sun StorageTek 9980 System
4ea4b951-9fc9-4f1f-b64e-69572a400fb4|Sun StorageTek 9970 System
2a94fb3c-0a18-11d6-90a8-c9c08656284f|Sun StorageTek 9960 System
2a918ae2-0a18-11d6-834a-c679537eebe7|Sun StorageTek 9910
f55c65ae-16a0-11d7-82ad-99701a4c6e31|Sun StorageTek 9900V Series Array
aea70032-21a1-11d6-900d-e576a4de8318|Network Storage

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