# Linux Volume Management Introduction to Linux Volumes and AWS EBS #### **1\. Understanding Linux Volumes** In Linux, a **volume** refers to a storage unit that the operating system recognizes as a single entity. It can be a physical partition on a hard disk, a logical volume, or even a virtual disk in cloud environments. #### **Types of Storage in Linux** * **Physical Volumes (PV):** Direct partitions on the disk, such as `/dev/sda1`. * **Logical Volumes (LV):** Created using Logical Volume Manager (LVM) to allow flexible disk management. * **Mount Points:** Directories where volumes are mounted, such as `/mnt` or `/home` #### **2\. What is AWS EBS (Elastic Block Store)?** Amazon **EBS (Elastic Block Store)** is a scalable block storage service for **EC2 (Elastic Compute Cloud)** instances. It functions like a traditional hard drive but is designed for high availability and durability in AWS. ##### **Key Features of AWS EBS** * **Persistent Storage:** Unlike instance store volumes, EBS volumes persist even after an EC2 instance is stopped or terminated. * **Scalability:** Easily resize volumes without downtime using Elastic Volumes. * **Performance:** Available in different types (SSD, HDD) to match workload needs. * **Backup and Snapshots:** Supports snapshots for data backup and recovery. #### **3\. AWS EBS Volume Types** | Volume Type | Description | Use Case | | --- | --- | --- | | **gp3 (General Purpose SSD)** | High-performance, low-latency SSD | Web servers, databases | | **gp2 (General Purpose SSD)** | Older generation, balanced SSD | General workloads | | **io1/io2 (Provisioned IOPS SSD)** | High IOPS performance | Databases, high-transaction apps | | **st1 (Throughput Optimized HDD)** | High throughput, lower cost | Big data, log processing | | **sc1 (Cold HDD)** | Lowest cost, for rarely accessed data | Archives, backups | #### **4\. Attaching an EBS Volume to an EC2 Instance** ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1740504089133/cd8ad6ec-78e4-4cca-8b40-75fd2d924b92.png align="center") To attach and mount an EBS volume in AWS, follow these steps: ##### **Step 1: Create and Attach EBS Volume** 1. Go to AWS **EC2 Dashboard** → **Volumes** → **Create Volume**. 2. Select the volume type, size, and availability zone. 3. Attach the volume to an EC2 instance. ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1740503578620/3f7532e0-d0fd-4991-9932-2306096582a6.png align="center") ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1740503633342/8c562acc-3371-4176-9d7b-80c875a10a05.png align="center") ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1740503751848/e97e1876-2870-4e6b-b87b-77d7e2db2c8c.png align="center") ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1740503797412/a03ea95c-e82e-4213-a6a9-eb2f4e1fe5e1.png align="center") ![](https://cdn.hashnode.com/res/hashnode/image/upload/v1740503822152/edd1e801-e3b7-4ced-ba72-a36ac69c2afb.png align="center") ```plaintext ubuntu@ip-172-31-43-63:~$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS loop0 7:0 0 26.3M 1 loop /snap/amazon-ssm-agent/9881 loop1 7:1 0 73.9M 1 loop /snap/core22/1722 loop2 7:2 0 44.4M 1 loop /snap/snapd/23545 xvda 202:0 0 8G 0 disk ├─xvda1 202:1 0 7G 0 part / ├─xvda14 202:14 0 4M 0 part ├─xvda15 202:15 0 106M 0 part /boot/efi └─xvda16 259:0 0 913M 0 part /boot ubuntu@ip-172-31-43-63:~$ df -h Filesystem Size Used Avail Use% Mounted on /dev/root 6.8G 1.7G 5.1G 26% / tmpfs 479M 0 479M 0% /dev/shm tmpfs 192M 876K 191M 1% /run tmpfs 5.0M 0 5.0M 0% /run/lock /dev/xvda16 881M 76M 744M 10% /boot /dev/xvda15 105M 6.1M 99M 6% /boot/efi tmpfs 96M 12K 96M 1% /run/user/1000 ubuntu@ip-172-31-43-63:~$ ``` Volume attached to EC2 Instance ```plaintext ubuntu@ip-172-31-43-63:~$ lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS loop0 7:0 0 26.3M 1 loop /snap/amazon-ssm-agent/9881 loop1 7:1 0 73.9M 1 loop /snap/core22/1722 loop2 7:2 0 44.4M 1 loop /snap/snapd/23545 xvda 202:0 0 8G 0 disk ├─xvda1 202:1 0 7G 0 part / ├─xvda14 202:14 0 4M 0 part ├─xvda15 202:15 0 106M 0 part /boot/efi └─xvda16 259:0 0 913M 0 part /boot xvdf 202:80 0 10G 0 disk xvdg 202:96 0 12G 0 disk xvdh 202:112 0 14G 0 disk ``` ### Physical vs Logical Volumes vs Volume Groups in Linux (LVM) * **Physical Volume (PV):** * Represents actual storage devices or partitions (e.g., `/dev/sda1`). * The raw storage units used in **LVM (Logical Volume Manager)**. * Created using `pvcreate` command. * **Volume Group (VG):** * A collection of **Physical Volumes (PVs)** combined into a single storage pool. * Allows flexible allocation of storage space. * Created using `vgcreate` command. * **Logical Volume (LV):** * A virtual partition created within a **Volume Group (VG)**. * Can be resized dynamically without affecting the underlying physical disks. * Created using `lvcreate` command. ### **Hierarchy in LVM** **Physical Volumes (PVs) → Volume Groups (VGs) → Logical Volumes (LVs)** ### Managing AWS EBS on EC2 Instances Steps to Create Physical Volumes in LVM on Ubuntu 1. Switch to Root User 2. Access LVM Shell 3. Check Existing Physical Volumes 4. Create New Physical Volumes 5. Verify Physical Volumes ```plaintext ubuntu@ip-172-31-43-63:~$ sudo su root@ip-172-31-43-63:/home/ubuntu# lvm lvm> pvs lvm> pvcreate /dev/xvdf /dev/xvdg /dev/xvdh Physical volume "/dev/xvdf" successfully created. Physical volume "/dev/xvdg" successfully created. Physical volume "/dev/xvdh" successfully created. lvm> pvs PV VG Fmt Attr PSize PFree /dev/xvdf lvm2 --- 10.00g 10.00g /dev/xvdg lvm2 --- 12.00g 12.00g /dev/xvdh lvm2 --- 14.00g 14.00g ``` Steps to Create a Volume Group in LVM on Ubuntu 1. Create a Volume Group This combines both physical volumes into a single storage pool called `tws_vg`. 2. Verify the Volume Group ```plaintext lvm> vgcreate tws_vg /dev/xvdf /dev/xvdg Volume group "tws_vg" successfully created lvm> vgs VG #PV #LV #SN Attr VSize VFree tws_vg 2 0 0 wz--n- 21.99g 21.99g ``` Steps to Create a Logical Volume in LVM on Ubuntu 1. Create a Logical Volume * `-L 10G` → Allocates **10GB** to the logical volume. * `-n tws_lv` → Names the logical volume as `tws_lv`. * `tws_vg` → Specifies the volume group where the LV is created. 2. Verify Logical Volumes * This will display information about the **logical volume**, such as size, VG name, and attributes. ```plaintext lvm> lvcreate -L 10G -n tws_lv tws_vg Logical volume "tws_lv" created. lvm> lvs LV VG Attr LSize Pool Origin Data% Meta% Move Log Cpy%Sync Convert tws_lv tws_vg -wi-a----- 10.00g ``` ### LVM Logical Volume Mounting Steps 1. Create a Mount Point * This creates a directory where the logical volume will be mounted. 2. Format the Logical Volume with ext4 Filesystem * This formats `tws_lv` with the **ext4** filesystem. * Displays **UUID** and **superblock backup locations**. 3. Mount the Logical Volume - Mounts the **LV** to `/mnt/tws_lv_mount`. 4. Verify Mounting with `df -h` ```plaintext root@ip-172-31-43-63:/home/ubuntu# mkfs.ext4 /dev/tws_vg/tws_lv mke2fs 1.47.0 (5-Feb-2023) Creating filesystem with 2621440 4k blocks and 655360 inodes Filesystem UUID: abcce1ea-e1b2-41ec-9cf6-29514a3d2920 Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632 Allocating group tables: done Writing inode tables: done Creating journal (16384 blocks): done Writing superblocks and filesystem accounting information: done root@ip-172-31-43-63:/home/ubuntu# mount /dev/tws_vg/tws_lv /mnt/tws_lv_mount root@ip-172-31-43-63:/home/ubuntu# df -h Filesystem Size Used Avail Use% Mounted on /dev/root 6.8G 1.7G 5.1G 26% / tmpfs 479M 0 479M 0% /dev/shm tmpfs 192M 908K 191M 1% /run tmpfs 5.0M 0 5.0M 0% /run/lock /dev/xvda16 881M 76M 744M 10% /boot /dev/xvda15 105M 6.1M 99M 6% /boot/efi tmpfs 96M 12K 96M 1% /run/user/1000 /dev/mapper/tws_vg-tws_lv 9.8G 24K 9.3G 1% /mnt/tws_lv_mount ``` ### Verification of LVM Mount and File Creation 1. Navigate to the Mounted Directory * This moves into the mounted **Logical Volume (LV) directory**. 2. Create a New Directory (`devops`) * This creates a **subdirectory** named `devops` inside the mounted LV. 3. Verify the Directory Creation 4. Navigate to the `devops` Directory 5. Create a New File (`hello.txt`) 6. Go Back to Home Directory & Verify the File Content ```plaintext root@ip-172-31-43-63:/home/ubuntu# cd /mnt/tws_lv_mount/ root@ip-172-31-43-63:/mnt/tws_lv_mount# mkdir devops root@ip-172-31-43-63:/mnt/tws_lv_mount# ls devops lost+found root@ip-172-31-43-63:/mnt/tws_lv_mount# cd devops/ root@ip-172-31-43-63:/mnt/tws_lv_mount/devops# vim hello.txt root@ip-172-31-43-63:/mnt/tws_lv_mount/devops# cd root@ip-172-31-43-63:~# cat /mnt/tws_lv_mount/devops/hello.txt This is LVM Seession ``` ### Steps to Unmount and Remount the LVM Volume 1. Unmount the LVM Volume **Unmounts** the logical volume, making its contents **temporarily inaccessible**. 2. Try to Access the File (Fails) - Since the LV is **unmounted**, the file is no longer accessible. 3. Remount the LVM Volume - **Mounts** the logical volume back to `/mnt/tws_lv_mount`. 4. Verify the File Again -The file is restored, confirming that **data is preserved inside the Logical Volume (LV).** ```plaintext root@ip-172-31-43-63:~# umount /mnt/tws_lv_mount/ root@ip-172-31-43-63:~# cat /mnt/tws_lv_mount/devops/hello.txt cat: /mnt/tws_lv_mount/devops/hello.txt: No such file or directory root@ip-172-31-43-63:~# mount /dev/tws_vg/tws_lv /mnt/tws_lv_mount root@ip-172-31-43-63:~# cat /mnt/tws_lv_mount/devops/hello.txt This is LVM Seession ``` ### Steps to Format and Mount a New Disk (`/dev/xvdh`) 1. Create a Mount Point This creates a **directory** where the new disk will be mounted. 2. Verify the Mount Points 3. Format `/dev/xvdh` with `ext4` Filesystem * The system warns that `/dev/xvdh` contains an **LVM2\_member filesystem**. * You **proceeded anyway** by typing `y`. * This confirms the **ext4 filesystem** has been successfully created 4. Mount the Formatted Disk Mounts `/dev/xvdh` to `/mnt/tws_disk_mount`. 5. Verify the Mounted Disk ```plaintext root@ip-172-31-43-63:~# mkdir /mnt/tws_disk_mount root@ip-172-31-43-63:~# cd /mnt/ root@ip-172-31-43-63:/mnt# ls tws_disk_mount tws_lv_mount root@ip-172-31-43-63:/mnt# mkfs -t ext4 /dev/xvdh mke2fs 1.47.0 (5-Feb-2023) /dev/xvdh contains a LVM2_member file system Proceed anyway? (y,N) y Creating filesystem with 3670016 4k blocks and 917504 inodes Filesystem UUID: ef6f59fe-bb3e-4109-b9b9-f4c09df7b92a Superblock backups stored on blocks: 32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208 Allocating group tables: done Writing inode tables: done Creating journal (16384 blocks): done Writing superblocks and filesystem accounting information: done root@ip-172-31-43-63:/mnt# cd root@ip-172-31-43-63:~# mount /dev/xvdh /mnt/tws_disk_mount/ root@ip-172-31-43-63:~# df -h Filesystem Size Used Avail Use% Mounted on /dev/root 6.8G 1.7G 5.1G 26% / tmpfs 479M 0 479M 0% /dev/shm tmpfs 192M 908K 191M 1% /run tmpfs 5.0M 0 5.0M 0% /run/lock /dev/xvda16 881M 76M 744M 10% /boot /dev/xvda15 105M 6.1M 99M 6% /boot/efi tmpfs 96M 12K 96M 1% /run/user/1000 /dev/mapper/tws_vg-tws_lv 9.8G 32K 9.3G 1% /mnt/tws_lv_mount /dev/xvdh 14G 24K 13G 1% /mnt/tws_disk_mount ``` ### Steps to Extend a Logical Volume (`tws_lv`) by 5GB 1. Extend the Logical Volume (`lvextend`) This increased the Logical Volume (`tws_lv`) by **5GB**. ```plaintext lvm> lvextend -L +5G /dev/tws_vg/tws_lv Size of logical volume tws_vg/tws_lv changed from 10.00 GiB (2560 extents) to 15.00 GiB (3840 extents). Logical volume tws_vg/tws_lv successfully resized. ``` 1. Verify the Logical Volume Size ```plaintext root@ip-172-31-43-63:/home/ubuntu# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS loop0 7:0 0 26.3M 1 loop /snap/amazon-ssm-agent/9881 loop1 7:1 0 73.9M 1 loop /snap/core22/1722 loop2 7:2 0 44.4M 1 loop /snap/snapd/23545 xvda 202:0 0 8G 0 disk ├─xvda1 202:1 0 7G 0 part / ├─xvda14 202:14 0 4M 0 part ├─xvda15 202:15 0 106M 0 part /boot/efi └─xvda16 259:0 0 913M 0 part /boot xvdf 202:80 0 10G 0 disk └─tws_vg-tws_lv 252:0 0 15G 0 lvm /mnt/tws_lv_mount xvdg 202:96 0 12G 0 disk └─tws_vg-tws_lv 252:0 0 15G 0 lvm /mnt/tws_lv_mount xvdh 202:112 0 14G 0 disk /mnt/tws_disk_mount ``` ### LVM Display Commands in Linux After creating Physical Volumes (PV), Volume Groups (VG), and Logical Volumes (LV), you can use the following commands to check their details: 1\. Display Physical Volume Details ```plaintext lvm> pvdisplay --- Physical volume --- PV Name /dev/xvdf VG Name tws_vg PV Size 10.00 GiB / not usable 4.00 MiB Allocatable yes PE Size 4.00 MiB Total PE 2559 Free PE 2559 Allocated PE 0 PV UUID Z0FCJ2-NMWX-UIy8-PF4G-fdmN-NY0k-v7dKDN --- Physical volume --- PV Name /dev/xvdg VG Name tws_vg PV Size 12.00 GiB / not usable 4.00 MiB Allocatable yes PE Size 4.00 MiB Total PE 3071 Free PE 511 Allocated PE 2560 PV UUID zBY2JO-5Bm8-zrJ6-F18H-nVHB-ocEm-NXiuLL "/dev/xvdh" is a new physical volume of "14.00 GiB" --- NEW Physical volume --- PV Name /dev/xvdh VG Name PV Size 14.00 GiB Allocatable NO PE Size 0 Total PE 0 Free PE 0 Allocated PE 0 PV UUID ue1zCy-DLGw-euDq-QuDr-WgsP-koJu-UwXkTv ``` 2\. Display Volume Group Details ```plaintext lvm> vgdisplay --- Volume group --- VG Name tws_vg System ID Format lvm2 Metadata Areas 2 Metadata Sequence No 2 VG Access read/write VG Status resizable MAX LV 0 Cur LV 1 Open LV 0 Max PV 0 Cur PV 2 Act PV 2 VG Size 21.99 GiB PE Size 4.00 MiB Total PE 5630 Alloc PE / Size 2560 / 10.00 GiB Free PE / Size 3070 / 11.99 GiB VG UUID WgOCgI-QyP4-Z1jP-LauN-4fZa-KTEG-9l92ZS ``` 3. Display Logical Volume Details ```plaintext lvm> lvdisplay --- Logical volume --- LV Path /dev/tws_vg/tws_lv LV Name tws_lv VG Name tws_vg LV UUID KJ8maX-zp5g-wyQa-vFho-92P4-j3QE-K2ije1 LV Write Access read/write LV Creation host, time ip-172-31-43-63, 2025-02-25 17:37:26 +0000 LV Status available # open 0 LV Size 10.00 GiB Current LE 2560 Segments 1 Allocation inherit Read ahead sectors auto - currently set to 256 Block device 252:0 ``` ## Conclusion We successfully managed **LVM storage** on Ubuntu by: ✅ Creating **Physical Volumes (PV)**, **Volume Group (VG)**, and **Logical Volume (LV)** ✅ Formatting and mounting the **LV (**`tws_lv`) and a separate **disk (**`xvdh`) ✅ Extending the **LV by 5GB** and resizing the filesystem ✅ Verifying the updated **storage and filesystem size** This demonstrates **efficient LVM management**, allowing **flexible and scalable storage allocation** in Linux.