# Day 13 – Linux Volume Management (LVM) ## Introduction Today I learned one of the most important Linux storage management concepts: > Logical Volume Management (LVM) Traditional disk partitions are fixed in size and difficult to resize after creation. LVM solves this problem by providing flexible storage management. I also learned how AWS EBS volumes work with Linux instances and how additional storage can be attached, mounted, and managed dynamically. This is a critical skill for Linux administrators, cloud engineers, and DevOps professionals because production systems frequently require storage expansion without downtime. * * * ## My Learning Notes ![](https://cdn.hashnode.com/uploads/covers/688917fb6698deed76cee88e/d6bf06d0-65cd-40f5-bd8c-ad4de5785511.png align="center") Page No 2 ![](https://cdn.hashnode.com/uploads/covers/688917fb6698deed76cee88e/410dab39-a854-4e92-8d06-1d047bffec7b.png align="center") * * * # Understanding Linux Storage Before working with LVM, I reviewed some basic storage commands. ## List Block Devices ```bash lsblk ``` Purpose: * Displays all block devices attached to the system. * Shows disks, partitions, and mount points. * * * ## Check Disk Usage ```bash df -h ``` Purpose: * Displays available and used storage. * Shows mounted file systems. These commands help understand the current storage layout before making any modifications. * * * # AWS Elastic Block Storage (EBS) I learned how additional EBS volumes can be attached to an EC2 instance. ### Steps 1. Open AWS Console 2. Navigate to Elastic Block Store → Volumes 3. Create a new volume 4. Select size and availability zone 5. Attach the volume to the EC2 instance Example device names: ```text /dev/sdf /dev/sdg /dev/sdh ``` Inside the Linux instance, these may appear as: ```text /dev/xvdf /dev/xvdg /dev/xvdh ``` One important observation: > Attaching a volume only makes it visible to Linux. It does not make the storage usable until it is formatted and mounted. * * * # Understanding LVM Architecture LVM works in three layers: ```text Physical Volume (PV) ↓ Volume Group (VG) ↓ Logical Volume (LV) ↓ Filesystem ↓ Mount Point ``` ### Physical Volume (PV) A physical disk or block device. Examples: ```text /dev/xvdf /dev/xvdg /dev/xvdh ``` * * * ### Volume Group (VG) A storage pool created by combining one or more physical volumes. Example: ```text tws_vg ``` * * * ### Logical Volume (LV) A virtual partition created from the Volume Group. Example: ```text tws_lv ``` Logical Volumes can be resized later without repartitioning the disk. * * * # Creating Physical Volumes Command: ```bash pvcreate /dev/xvdf /dev/xvdg /dev/xvdh ``` Purpose: * Converts block devices into Physical Volumes. Verify: ```bash pvs ``` * * * # Creating a Volume Group Command: ```bash vgcreate tws_vg /dev/xvdf /dev/xvdg ``` Purpose: * Combines physical volumes into a storage pool. Verify: ```bash vgs ``` * * * # Creating a Logical Volume Command: ```bash lvcreate -L 10G -n tws_lv tws_vg ``` Purpose: * Creates a 10 GB logical volume. Verify: ```bash lvs ``` * * * # Display Commands To view detailed information: ```bash pvdisplay ``` Displays physical volume details. ```bash vgdisplay ``` Displays volume group details. ```bash lvdisplay ``` Displays logical volume details. * * * # Mounting Volumes in Linux After creating a Logical Volume, it must be formatted and mounted. ### Create Mount Point ```bash mkdir /mnt/tws_lv_mount ``` * * * ### Format the Volume ```bash mkfs.ext4 /dev/tws_vg/tws_lv ``` Purpose: * Creates an ext4 filesystem. * * * ### Mount the Volume ```bash mount /dev/tws_vg/tws_lv /mnt/tws_lv_mount ``` Now the storage becomes usable. * * * # Understanding Attach vs Mount One concept that became very clear today: ### Attach AWS attaches the block storage to the VM. Example: ```text /dev/xvdf ``` Storage is connected but not usable. * * * ### Mount Linux mounts the storage to a directory. Example: ```text /mnt/tws_lv_mount ``` Storage becomes accessible and usable. * * * # Unmounting a Volume Command: ```bash umount /mnt/tws_lv_mount ``` Purpose: * Safely disconnects the filesystem. * * * # Managing AWS EBS Without LVM I also learned that EBS volumes can be mounted directly without creating Volume Groups and Logical Volumes. ### Create Mount Directory ```bash mkdir /mnt/tws_disk_mount ``` ### Format Disk ```bash mkfs -t ext4 /dev/xvdh ``` ### Mount Disk ```bash mount /dev/xvdh /mnt/tws_disk_mount ``` This directly uses the EBS volume. However, LVM provides greater flexibility for future storage expansion. * * * # Dynamic Storage Expansion Using LVM One of the biggest advantages of LVM is dynamic volume resizing. Example: Current Logical Volume: ```text 10 GB ``` Additional storage added: ```text +5 GB ``` Extend Logical Volume: ```bash lvextend -L +5G /dev/tws_vg/tws_lv ``` This increases the volume size without recreating partitions. This is extremely useful in production environments where storage requirements change over time. * * * # What I Learned ### 1\. LVM Provides Flexible Storage Management Storage can be resized dynamically without repartitioning. * * * ### 2\. Storage Becomes Usable Only After Mounting Attaching a disk is not enough. The filesystem must be created and mounted. * * * ### 3\. LVM Is Widely Used in Production Most enterprise Linux systems use: * Physical Volumes * Volume Groups * Logical Volumes because storage requirements constantly change. * * * # Key Commands Practiced ```bash lsblk df -h pvcreate pvs pvdisplay vgcreate vgs vgdisplay lvcreate lvs lvdisplay mkfs.ext4 mount umount lvextend ``` * * * # Final Thoughts Today was my first deep dive into Linux storage management. I learned how AWS EBS volumes interact with Linux systems, how LVM organizes storage into Physical Volumes, Volume Groups, and Logical Volumes, and how storage can be expanded dynamically without downtime. Understanding LVM is an important step toward becoming comfortable with real-world Linux administration and cloud infrastructure management. Day 13 completed. Still learning. Still improving. Still building.