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# Mount volume permanently

### List volumes

```
root@server:/# blkid

/dev/xvda1: LABEL="cloudimg-rootfs" UUID="ef263917-4ffc-4c36-880c-ae41d52b0d8e" TYPE="ext4"
/dev/xvdf: UUID="2c21a384-9e0e-4b44-b8d1-ceb452e8cc5c" TYPE="ext4"

root@server:/home/ubuntu# lsblk

NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0  32G  0 disk
└─xvda1 202:1    0  32G  0 part /
xvdf    202:80   0  32G  0 disk 
```

### Permanently mount

Mount volume `xvdf` to `/var/lib/mysql`

```
root@server:/# mount /dev/xvdf /var/lib/mysql
```

Recheck after mount

```
root@server:/# lsblk

NAME    MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
xvda    202:0    0  32G  0 disk
└─xvda1 202:1    0  32G  0 part /
xvdf    202:80   0  32G  0 disk /var/lib/mysql
```

Mount volume permanently - even after rebooting

```
root@server:/# vim /etc/fstab

UUID="2c21a384-9e0e-4b44-b8d1-ceb452e8cc5c" /data ext4 defaults  0 0

root@server:/# mount -fav
/                        : ignored
/var/lib/mysql           : already mounted
```

We must config `fstab` (permanent mount) based on **`UUID`** or  **`LABEL`** like this

```
LABEL=cloudimg-rootfs                       /                      ext4  defaults,discard  0 0
UUID="c46cf311-d31b-41ce-bce5-5d8ad0a6b109" /var/lib/elasticsearch ext4  defaults,nofail  0 2
UUID="2c21a384-9e0e-4b44-b8d1-ceb452e8cc5c" /data                  ext4  defaults  0 0
```

**DON'T config based on device name** like this fuck

```
LABEL=cloudimg-rootfs	   /	                  ext4	defaults,discard	0 0
/dev/nvme1n1p1             /var/lib/elasticsearch ext4  defaults,nofail     0 2
/dev/xvdf                  /data                  ext4  defaults            0 0
```

### Mountfuck

![Entire fucking dir in fuckin /var/lib/elasticsearch](/files/-LXP1hKCjsmH8PWFRnWv)

Root cause: <https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/nvme-ebs-volumes.html>

> EBS uses single-root I/O virtualization (SR-IOV) to provide volume attachments on Nitro-based instances using the NVMe specification.These devices rely on standard NVMe drivers on the operating system.These drivers typically discover attached devices by scanning the PCI bus during instance boot, and create device nodes based on the order in which the devices respond, not on how the devices are specified in the block device mapping.In Linux, NVMe device names follow the pattern /dev/nvme\<x>n\<y>, where \<x> is the enumeration order, and, for EBS, \<y> is 1.Occasionally, devices can respond to discovery in a different order in subsequent instance starts, which causes the device name to change.

So, if we use NVMe disk for some new types of AWS EC2, please note that the **device name is nearly randomize after each reboot**. It means if we have 2 NVMe disks on one EC2 vm, so we cannot know which device name delegate to which real disk.

```
/dev/nvme1n1p1
/dev/nvme0n1p1
```

### Reference

1. <https://askubuntu.com/questions/45607/how-to-mount-partition-permanently/45618#45618>
2. <https://docs.oracle.com/cloud/latest/computecs_common/OCSUG/GUID-075D8B13-A089-4A81-BB5C-DD7B09995C47.htm#OCSUG276>