Format and mount a new data disk attached to an ECS instance before use.
Determine whether initialization is needed and which method to use based on your disk size and operating system.
When to initialize
Initialize only empty new data disks:
Data disks created with Linux instances
Empty data disks created separately
The following disks do not require initialization:
System disks and data disks created with Windows instances — automatically partitioned and mounted.
Disks created from a snapshot — already contain data. Mount the file system (Linux) or bring the disk online (Windows). See Step 8 in "Create a data disk from a snapshot."
Disks used for block storage performance testing — no file system required.
Disks accessed directly by databases or applications — no file system required.
Choose a method
Select a guide based on your disk size and operating system.
For disks ≤ 2 TiB:
Operating system | Initialization tool | Partition format | Common file system | Guide |
Linux | Partition: Parted or fdisk; File system: e2fsprogs | GPT (recommended) or MBR | Ext4 or XFS | |
Windows | Disk Management | GPT (recommended) or MBR | NTFS |
For disks > 2 TiB:
Operating system | Initialization tool | Partition format | Common file system | Guide |
Linux | Partition: Parted; File system: e2fsprogs | GPT | Ext4 or XFS | |
Windows | Disk Management | GPT | NTFS |
On Linux, use Parted for disks > 2 TiB. fdisk does not support disks larger than 2 TiB.
Do you need to create partitions?
For a single-volume disk, skip partitioning and create a file system directly on the raw device. Partition only when you need multiple logical volumes on one disk (for example, separate /dev/vdb1 and /dev/vdb2).
Without partitioning, go directly to Step 3: Create and mount file systems in the Linux initialization guide.
Partition formats
Data disks support Master Boot Record (MBR) and GUID Partition Table (GPT) partition formats.
Format | Maximum partition size | Partition limit | Partition types | Recommended tool |
MBR | 2 TiB | 4 primary, or 3 primary + 1 extended | Primary, extended, and logical. Extended partitions subdivide into logical partitions; logical partitions are unlimited. | Linux: fdisk or Parted; Windows: Disk Management |
GPT | 18 EiB (1 EiB = 1,048,576 TiB); The maximum capacity of an Alibaba Cloud disk is 64 TiB. | Linux: unlimited; Windows: 128 | All partitions are primary — no extended or logical partitions. | Linux: Parted; Windows: Disk Management |
Use GPT if your disk exceeds 2 TiB or may be extended beyond 2 TiB. Repartitioning an MBR disk to exceed 2 TiB requires reformatting, which causes data loss.
Data disk device names on Linux
Linux assigns device names based on instance type and protocol:
Instance type | Protocol | Device name format | Examples |
I/O optimized | NVMe |
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I/O optimized | Other |
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Non-I/O optimized | — |
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