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Basic Storage Service Configuration Guide for File

OceanStor V3 Series V300R006

This document is applicable to OceanStor 2200 V3, 2600 V3, 5300 V3, 5500 V3, 5600 V3, 5800 V3, 6800 V3, 18500 V3, and 18800 V3. It describes the basic storage services and explains how to configure and manage them.
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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).
Basic Concepts

Basic Concepts

Get yourself started with basic concepts.

  • Disk domain

    A domain consisting of the same or different types of disks. Disk domains are isolated from each other. Therefore, services carried by different disk domains do not affect each other in terms of performance and faults if any.

  • Storage pool

    A storage resource container, which is created under a disk domain. The storage resources used by application servers are called up from storage pools.

  • Storage tier

    A set of storage media providing the same performance in a storage pool. Storage tiers are used to manage storage media with different performance and provide appropriate storage space for applications having different performance demands.

  • Chunk (CK)

    A set of consecutive physical spaces of a fixed size on a disk.

  • Chunk group (CKG)

    A logical set of CKs on different disks. A CKG has the properties of a redundant array of independent disks (RAID) group.

  • Block virtualization

    A new type of RAID technology. Block virtualization divides disks into multiple CKs of a fixed size and organizes them into multiple CKGs. When a disk fails, the disks of the CKG where the CKs in the faulty disk reside also participate in reconstruction. This significantly increases the disks involved in the reconstruction, improving the data reconstruction speed. In addition, block virtualization distributes data to all the disks in a storage system and leverages the I/O processing capability of the storage system.

  • Extent

    A logical storage space with a fixed size divided from a CKG. The size of the space ranges from 512 KB to 64 MB. The default size is 4 MB. Extent is the smallest unit for space application and release in a storage pool.

  • Grain

    In file system mode, extents are further divided into grains. The size of grains ranges from 4 KB to 64 KB. Grains are basic units that constitute a file system.

  • Hot spare space

    Space used for faulty block data reconstruction in block virtualization. When a CK is faulty, the system lets a CK of the hot spare space take over and instructs the other CKs in the CKG to perform data reconstruction using the hot spare space. This ensures data integrity and read/write performance.

  • Reconstruction
    A process of restoring the data saved on a faulty disk to hot spare CKs and replacing the CKs on the faulty disk with the hot spare CKs. During data reconstruction, valid data and parity data must be read and processed to restore the data saved on a faulty disk to hot spare space, thereby ensuring data security and reliability. Traditional reconstruction technologies allow only all disks in the same RAID group as the faulty disk to participate in reconstruction. RAID 2.0+ technology enables all disks of the same type and in the same disk domain as the faulty disk to participate in reconstruction, boosting data reconstruction speed and shortening data recovery duration.

    Data on other disks is read for reconstruction. To prevent reconstruction failures, service interruption, and data loss, do not remove other disks of the same type as the faulty disk in the disk domain where the faulty disk resides.

  • Thin file system

    A logical space accessible to a host. A thin file system is configured with an initial capacity when being created and dynamically allocated required storage resources when its available capacity is insufficient.

  • Thick file system

    A logical space accessible to a host. A thick file system is allocated a fixed capacity of storage resources according to the capacity specified when being created using the automatic provisioning technology.

  • Quota tree

    The root directory of a file system. You can manage file quantity or storage space under a quota tree.

  • File system quota

    A file system quota can restrict resource usage. Huawei provides SmartQuota for quota management.

    There are three types of quotas: directory quota, user quota, and user group quota.

    • Directory quota: restricts the maximum available space or number of files in a directory. The storage system supports the default directory quota. The default directory quota applies to all quota trees in a file system. If the default directory quota is configured but no other directory quota is configured for a new quota tree, the quota tree uses the default directory quota to restrict the available space and number of files.
    • User quota: restricts the space or number of files that can be used by a user. The storage system supports the default user quota. The default user quota applies to all users in a file system or quota tree. If the default user quota is configured but no other user quota is configured for a user, the default user quota is used to restrict the available space and number of files for the user.
    • User group quota: restricts the space or number of files that can be used by a user group. The space or number of files used by all members in a user group cannot exceed the user group quota. The storage system supports the default user group quota. The default user group quota applies to all user groups in a file system or quota tree. If the default user group quota is configured but no other user group quota is configured for a user group, the default user group quota is used to restrict the available space and number of files for the user group.

    The following two quota types are involved in each preceding quota type.

    • Space quota: maximum capacity of a quota tree in a file system
    • File quantity quota: maximum number of files under a quota tree in a file system

    A quota can be soft and hard.

    • For file quantity, a hard quota specifies the maximum number of files allowed in a quota tree, while, a soft quota is an alarm threshold of file quantity.
    • For storage space, a hard quota specifies the maximum capacity of storage space in a quota tree, while, a soft quota is an alarm threshold in quota tree space.
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Updated: 2019-07-12

Document ID: EDOC1000138856

Views: 62169

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