NetApp
7-mode/HA pair/V-Series : LUNs : Understanding LUNs : Guidelines for working with volumes that contain LUNs
Guidelines for working with volumes that contain LUNs
When you work with volumes that contain LUNs, you must change the default settings for Snapshot copies. You can also optimize LUN layout to simplify administration.
Data ONTAP Snapshot copies are required for many optional features, such as the SnapMirror feature, SyncMirror feature, dump and restore, and ndmpcopy.
When you create a volume, Data ONTAP automatically:
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Reserves 20 percent of the space for Snapshot copies
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Schedules Snapshot copies
Because the internal scheduling mechanism for taking Snapshot copies within Data ONTAP has no means of ensuring that the data within a LUN is in a consistent state, it is recommended that you change these Snapshot copy settings by performing the following tasks:
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Turn off the automatic Snapshot copy schedule.
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Delete all existing Snapshot copies.
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Set the percentage of space reserved for Snapshot copies to zero.
It is strongly recommended that you use the following guidelines to create traditional or FlexVol volumes that contain LUNs:
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Do not create any LUNs in the system’s root volume. Data ONTAP uses this volume to administer the storage system. The default root volume is /vol/vol0.
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Ensure that no other files or directories exist in a volume that contains a LUN.
If this is not possible and you are storing LUNs and files in the same volume, use a separate qtree to contain the LUNs.
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If multiple hosts share the same volume, create a qtree on the volume to store all LUNs for the same host. This is a recommended best practice that simplifies LUN administration and tracking.
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Ensure that the volume option create_ucode is set to on.
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To simplify management, use naming conventions for LUNs and volumes that reflect their ownership or the way that they are used.
See the Data ONTAP Storage Management Guide for more information.
Parent Topic: Storage node