# 持久化块设备命名

## 持久化命名方式

有4种不同的方式可以持久化命名设备：

* `by-label`
* `by-uuid`
* `by-id`
* `by-path`

对于使用GPT(GUID Partition Table)，另外增加了2种命名方式：

* `by-partlabel`
* `by-partuuid`

> ??? 如果磁盘通过`parted`工具划分分区，并且将分区表设置为`GPT`的时候，才能使用`PARTUUID`来标识磁盘分区。难怪我使用fdisk将划分成dos分区，`mkfs.ext4`之后只看到`UUID`，没有看到`PARTUUID`
>
> 注意：使用[Disk cloning](https://wiki.archlinux.org/index.php/Disk_cloning)创建2块不同的数据盘会使用相同的命名。

* `lsblk -f`命令显示

```
$ lsblk -f
NAME   FSTYPE LABEL  UUID                                 MOUNTPOINT
sda
├─sda1 vfat          D37E-2016                            /boot/efi
└─sda2 ext4   rootfs bb6a7d65-996d-4883-98d3-eef82f836edd /
```

对于使用`GPT`分区表的磁盘，则应该使用`blkid`（可以显示`PARTUUID`）:

```
$ blkid
/dev/sda1: UUID="D37E-2016" TYPE="vfat" PARTUUID="d89e3f09-b4d2-48e2-9d7a-291e65368d8c"
/dev/sda2: LABEL="rootfs" UUID="bb6a7d65-996d-4883-98d3-eef82f836edd" TYPE="ext4" PARTLABEL="rootfs" PARTUUID="dd121a11-7454-4e71-abdc-397f08f515f6"
```

## `by-label`

虽然每个文件系统类型都可以具有一个label。所有的分区都在`/dev/disk/by-label`目录下有一个分区入口。这个目录是动态创建和销毁的，依赖于是否使用了label来创建分区

```
$ ls -l /dev/disk/by-label/
total 0
lrwxrwxrwx 1 root root 10 Mar 24 23:35 rootfs -> ../../sda2
```

注意：文件系统的label可以修改。以下是一些在常见文件系统修改label方法：

* `swap`（使用`util-linux`工具包）:

```
swaplabel -L <label> /dev/XXX
```

* `ext2/3/4`（使用`e2fsprogs`工具）：

```
e2label /dev/XXX <label>
```

* `btrfs`

```
btrfs filesystem label /dev/XXX <label>
```

* `reiserfs`

```
reiserfstune -l <label> /dev/XXX
```

* `jfs`

```
jfs_tune -L <label> /dev/XXX
```

* `xfs`

```
xfs_admin -L <label> /dev/XXX
```

* `fat/vfat`

```
fatlabel /dev/XXX <label>
mlabel -i /dev/XXX ::<label>
```

* `exfat`

```
exfatlabel /dev/XXX <label>
```

* `ntfs`

```
ntfslabel /dev/XXX <label>
```

* `zfs`

不支持`/dev/disk/by-label`

## `by-uuid`

## 参考

* [Persistent block device naming](https://wiki.archlinux.org/index.php/persistent_block_device_naming)


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://huataihuang.gitbook.io/cloud-atlas-draft/os/linux/storage/disk/persistent_block_device_naming.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.