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tech_docs/linux/LVM.md

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+Sure, let's outline the CLI commands to set up your system using LVM for VM storage, which combines simplicity and performance, especially focusing on utilizing SSDs for your VMs for better performance. This setup will use `sdd` and `sde` (your SSDs) for VM storage and snapshots.
+
+### 1. Prepare the SSDs for LVM Use
+
+First, you need to create physical volumes (PVs) on your SSDs. This step initializes the disks for use by LVM. Ensure any important data on these disks is backed up before proceeding, as this will erase existing data.
+
+```bash
+pvcreate /dev/sdd
+pvcreate /dev/sde
+```
+
+### 2. Create a Volume Group
+
+Next, create a volume group (VG) that combines these physical volumes. This provides a pool of disk space from which logical volumes can be allocated. We'll name this volume group `vg_ssd` for clarity.
+
+```bash
+vgcreate vg_ssd /dev/sdd /dev/sde
+```
+
+### 3. Create Logical Volumes for VMs
+
+Now, create logical volumes (LVs) within `vg_ssd` for your VMs. Adjust the size (`-L`) according to your needs. Here's an example of creating a 50GB logical volume for a VM:
+
+```bash
+lvcreate -L 50G -n vm1_storage vg_ssd
+```
+
+Repeat this step for as many VMs as you need, adjusting the name (`vm1_storage`, `vm2_storage`, etc.) and size each time.
+
+### 4. Formatting and Mounting (Optional)
+
+If you plan to directly attach these logical volumes to VMs, you might not need to format or mount them on the host system. Proxmox can use the LVM volumes directly. However, if you need to format and mount for any reason (e.g., for initial setup or data transfer), here's how you could do it for one VM storage volume:
+
+```bash
+mkfs.ext4 /dev/vg_ssd/vm1_storage
+mkdir /mnt/vm1_storage
+mount /dev/vg_ssd/vm1_storage /mnt/vm1_storage
+```
+
+Replace `ext4` with your preferred filesystem if different.
+
+### 5. Using LVM Snapshots
+
+To create a snapshot of a VM's logical volume, use the `lvcreate` command with the snapshot option (`-s`). Here's how to create a 10GB snapshot for `vm1_storage`:
+
+```bash
+lvcreate -L 10G -s -n vm1_storage_snapshot /dev/vg_ssd/vm1_storage
+```
+
+This creates a snapshot named `vm1_storage_snapshot`. Adjust the size (`-L`) based on the expected changes and the duration you plan to keep the snapshot.
+
+### Reverting to a Snapshot
+
+If you need to revert a VM's storage to the snapshot state:
+
+```bash
+lvconvert --merge /dev/vg_ssd/vm1_storage_snapshot
+```
+
+This will merge the snapshot back into the original volume, reverting its state.
+
+### Conclusion
+
+This setup leverages your SSDs for VM storage, offering a balance between performance and simplicity. By using LVM, you maintain flexibility in managing storage space and snapshots, which can be especially useful in a lab environment for experimenting and rolling back changes. Remember, the specific commands and sizes should be adjusted based on your actual storage needs and system configuration.