Scenarios and Precautions
Operation Scenarios
A newly created data disk cannot store data directly when mounted to a cloud server. You need to firstly initialise the data disk by creating partitions and formatting the data disk. Initialisation may involve the following steps:
l Creating partitions: In some cases, you must create partitions for initializing an EVS. A partition is a logically independent division of a hard disk and each partition can be treated as an independent hard disk. A partition can help you better organize and manage data, while allowing the use of different file systems or operating systems on the same hard disk.
l Formatting: Initialisation involves formatting an EVS to create a file system that can store files and data. With formatting, you can select different file system types, such as EXT4 and NTFS, as needed.
The initialization action applies only to newly created data disks that contain no data. Based on different EVS types and status, the initialization scenarios are as follows:
EVS Function Category | Status Description of EVS | Initialisation Scenario |
System Disk | System disks are automatically created when a cloud server or dedicated physical server is created. | No initialization is required and system disks can be used directly. |
Data disks containing data | For example, data disks created from a snapshot or backup, or data disks unmounted from another cloud server, with original data retained. | No initialization is required. Data on a data disk may be lost during initialization. |
Newly created data disks | A new data disk is created in the following two ways: Data disks that are automatically created when you create a cloud server or dedicated physical server. Data disks that are created and manually attached to a cloud server. | These data disks must be initialised before use. Select an appropriate partitioning form according to your business needs. |
Before You Begin
A data disk is attached to a cloud server and this data disk is not initialised.
Cautions
Disk partitioning and formatting are high-risk activities. Exercise caution with this action. The actions described in this topic apply only to a new data disk. An EVS created from a data source does not need to be initialised. An EVS of this kind contains data in the data source in its initial state. If you want to format a data disk containing data, back up the data in the EVS first to avoid data loss.
An MBR partition can only identify a partition whose capacity is smaller than or equal to 2 TB and a GPT partition can identify a partition whose capacity is larger than 2 TB. Therefore, use a GPT partition for a partition whose capacity is larger than 2 TB. The specific differences between two partitions are as follows:
Partitioning Form | Supported Maximum Disk Capacity | Supported Number of Partitions | Partitioning Tool |
MBR | 2TB | Four primary partitions Three primary partitions and one extended partition | For a Linux system: fdisk tool parted tool |
GPT
| 18EB (An EVS disk has a maximum capacity of 32 TB) | Unlimited number of partitions | Linux operating system: parted tool |
When an EVS is in use, the original data on the EVS will be deleted if the partition mode is changed. Therefore, exercise caution with selecting an EVS partition when initializing the EVS. Before switching to a GPT partition, back up data on the EVS before formatting the disk.