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SmartTier Feature Guide for Block

OceanStor V5 Series V500R007

This document is applicable to OceanStor 5110 V5, 5300 V5, 5500 V5, 5600 V5, 5800 V5, 6800 V5, 18500 V5, and 18800 V5. This document describes the working principle and application scenarios of the SmartTier (for block) feature. It also explains how to configure and manage the feature.
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Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Configuring a RAID Policy and Data Migration Granularity

Configuring a RAID Policy and Data Migration Granularity

When creating a storage pool, you can configure the data migration granularity and RAID policy. These configurations cannot be changed after being set.


Two or more types of disks are selected for creating a storage pool.


Data Migration Granularity

SmartTier moves data of a storage pool by data migration granularity or data block. With SmartTier enabled, the storage pool identifies the data activity in the unit of data block, and relocates the whole data block to the corresponding storage tier.

Define the data migration granularity when creating a storage pool. The value cannot be changed after being set. The default data migration granularity is 4 MB and you are advised to use the default value. For applications requiring a larger data relocation granularity, contact technical support engineers.

A small data migration granularity will result in efficient storage resource use, because this reduces the possibility that cold data is unnecessarily promoted along with hot data to consume excessive high-priority storage resources. However, a small data migration granularity is not suitable for scenarios such as streaming media and video surveillance requiring a larger data relocation granularity.

RAID Policy

The SmartTier provides each storage tier with a specific RAID policy. The SmartTier distributes data to the three storage tiers that use varied disk types and RAID levels. Therefore, the performance of the data is dependent not only on the performance of its storage pool but also on the performance of the lowest-priority storage tier.

Table 2-1 describes the recommended RAID policy for each storage tier.

Table 2-1 Recommended RAID policy for each storage tier

Storage Tier

Recommended RAID Policy


High-performance tier


RAID 10 features fast read and write, suitable for SSDs in the high-performance tier.

Performance tier


RAID 5 provides higher sequential write performance but lower read performance than RAID 10.

Capacity tier


RAID 6 features double parity, suitable for NL-SAS disks with a long reconstruction window.


A RAID policy is set when you are creating a storage pool or adding a storage tier into a pool. The RAID policy cannot be changed after being set.


If you want to evaluate the environment where the SmartTier is to be applied or add a storage tier into an existing environment, contact technical support engineers to work out a suitable RAID policy for each storage tier.


A storage pool configured with SmartTier needs to reserve free space because SmartTier requires extra data exchange space to dynamically migrate data.


  1. Go to the Storage Pool page.

    1. On the right navigation bar, click .

      The Provisioning page is displayed.

    2. On the page, click Storage Pool.

      The Storage Pool management page is displayed.

  2. Set a data migration granularity and RAID policy.

    1. On the storage pool management page, click Create. The Create Storage Pool wizard is displayed.
    2. In the Create Storage Pool dialog box, select the disk type and RAID policy for the storage pool.
    3. In the Create Storage Pool dialog box, click Advanced. The Advanced Properties Settings dialog box is displayed.
    4. In the Advanced Properties Settings dialog box, set Data Migration Granularity.
    5. Click OK. The data migration granularity is successfully configured.

Updated: 2019-07-11

Document ID: EDOC1000181474

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