File System And Storage Management PDF

File System and Storage Management  Foreword  This course describes the basic concepts of file systems, drive storage, and logical volume storage, how to manage and use the file system and storage, and some common operation commands. 2 Huawei Confidential  Objectiv...

File System and Storage Management  Foreword  This course describes the basic concepts of file systems, drive storage, and logical volume storage, how to manage and use the file system and storage, and some common operation commands. 2 Huawei Confidential  Objectives Upon completion of this course, you will understand:  Basic concepts of file systems and storage  How to mount and use drive storage  Methods of managing logical volumes 3 Huawei Confidential  Contents 1. Basic Concepts of File Systems File Systems  File Systems on openEuler  Swap Space 2. Mounting and Using Drive Storage 3. Logical Volume Management 4 Huawei Confidential File System Overview  A file system is a method and a data structure used by an operating system (OS) to identify files on a storage device or a partition, that is, a method of organizing files on a storage device. In an OS, a software structure that manages and stores file data is referred to as a file management system, or file system for short. User-friendly interfaces File system APIs Drive management software, similar Software stack for object to middleware control and management File system Underlying storage hardware, such as drives and partitions Objects and properties 5 Huawei Confidential File System Types and Application Scenarios Common File System Application Scenario FAT FAT, including the FAT16 and FAT32 variants, is used by Windows 9X OSs. NTFS is a security-based file system. It is a unique file system structure used by NTFS Windows NT. Windows 2000 adopts the updated NTFS 5.0. Network file system (NFS) is used for file sharing between UNIX systems over the NFS network. RAW RAW file system indicates that the drive is not processed or formatted. As the standard file system on GNU/Linux, extended file system (ext) features ext excellent file access performance and is more effective against small- and medium-sized files. ext variants include ext2, ext3, and ext4. A high-performance log file system developed for the IRIX OS by Silicon Graphics XFS in 1993. Later ported to the Linux kernel, it excels in large-file processing and provides smooth data transfer. 6 Huawei Confidential  Contents 1. Basic Concepts of File Systems  File Systems File Systems on openEuler  Swap Space 2. Mounting and Using Drive Storage 3. Logical Volume Management 7 Huawei Confidential File Systems on openEuler  The openEuler kernel is derived from Linux. The Linux kernel supports more than 10 types of file systems, such as Btrfs, JFS, ReiserFS, ext, ext2, ext3, ext4, ISO 9660, XFS, Minix, MSDOS, UMSDOS, VFAT, NTFS, HPFS, NFS, SMB, SysV and PROC. The following table describes the common file systems.  The default file system on openEuler is ext4. Common File System Description ext File system specially designed for Linux. The latest version is ext4. A high-performance log file system developed for the IRIX OS by Silicon Graphics in 1993. XFS Later ported to the Linux kernel, it excels in large-file processing and provides smooth data transfer. On Linux, VFAT is the name of the FAT (including FAT16 and FAT32) file systems of DOS and VFAT Windows. NFS Network file system (NFS) is used for file sharing between UNIX systems over the network. The standard file system for optical disc media. Linux supports this file system, allowing the ISO 9600 system to read optical discs and ISO image files, and burn optical discs. 8 Huawei Confidential  Contents 1. Basic Concepts of File Systems  File Systems  File Systems on openEuler Swap Space 2. Mounting and Using Drive Storage 3. Logical Volume Management 9 Huawei Confidential Swap Space  The swap space on Linux is a partition or a file on the drive. When the physical memory is insufficient, the resources that are not frequently accessed in the memory are saved to the preset swap space so that the memory occupied by the resources is released. In this way, the system has more memory to serve each process. When the content stored in the swap space is needed, the system loads the data in the swap space to the memory.  The sum of the physical memory and swap space size is the total virtual memory provided by the system.  Why is the swap space required?  More system memory: When the physical memory is insufficient, increasing the swap space size is more cost- effective than adding physical memory.  Overall system performance improvement: By moving infrequently used data to the swap space, the system has more memory for caching, accelerating the system I/O.  Enabling Linux hibernation: In many Linux distributions (such as Ubuntu), when the system hibernates, memory data is saved to the swap space. The saved data will be loaded to the memory upon next startup. 10 Huawei Confidential Swap Space Configuration  Linux has two forms of swap space: the swap partition and swap file. The swap partition is an independent drive that has no other file or content. The swap file is a special file in the file system and is independent from the system and data files.  Creating a swap partition: Run fdisk to create a partition, mkswap to create a swap partition, and swapon to enable the swap partition.  Creating a swap file: Create a file, run mkswap to format the file, and then run swapon to enable the swap file.  Recommended swap sizes RAM Size Recommended Swap Size ≤ 2 GB 2x RAM size 2 GB to 8 GB Same as RAM size > 8 GB 8 GB 11 Huawei Confidential  Contents 1. Basic Concepts of File Systems 2. Mounting and Using Drive Storage Drive Basics  Drive Partitioning  Formatting and Mounting 3. Logical Volume Management 12 Huawei Confidential Drive Types Storage Interface media types  IDE Hard disk drive  SCSI (HDD)  SATA Solid state drive (SSD)  SAS  FC 13 Huawei Confidential Drive Interface Description Drive Interface Description The earliest general standard for HDDs. All electronic integrated drives, Integrated Drive Electronics (IDE) including SCSI, adopt the IDE standard. SATA is distinct from IDE, which is also known as Parallel ATA (PATA). Serial ATA (SATA) Therefore, the IDE interface is often called the parallel port and the SATA interface is called the serial port. Drives that adopt the SCSI interface are SCSI drives. Serial Attached SCSI (SAS) is a serial implementation of the SCSI interface. SCSI drives are Small Computer System usually used on servers. Compared with PATA and SATA drives, SCSI Interface (SCSI) drives provide higher performance, stronger stability, and support hot swap. However, SCSI drives have disadvantages such as small capacity, loud noise, and high cost. FC interfaces enable drives to connect directly using optical fibers, Fibre Channel (FC) improving the I/O performance of high-throughput performance- intensive systems. 14 Huawei Confidential Viewing Drive Information on Linux (1)  fdisk -l is used to view information about all drives in the system, including mounted and unmounted drives. [root@openEuler ~]# fdisk -l Disk /dev/vda: 40 GiB, 42949672960 bytes, 83886080 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disklabel type: gpt Disk identifier: AA321D82-C833-4D3E-885C-52FC0ADF3860 Device Start End Sectors Size Type /dev/vda1 2048 411647 409600 200M EFI System /dev/vda2 411648 2508799 2097152 1G Linux filesystem /dev/vda3 2508800 83884031 81375232 38.8G Linux LVM Disk /dev/mapper/openeuler-root: 34.82 GiB, 37367054336 bytes, 72982528 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk /dev/mapper/openeuler-swap: 4 GiB, 4294967296 bytes, 8388608 sectors Units: sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes 15 Huawei Confidential Viewing Drive Information on Linux (2)  df -h is used to check the mounting status, spaces, and usage of the drives. [root@openEuler ~]# df -h Filesystem Size Used Avail Use% Mounted on devtmpfs 1.2G 0 1.2G 0% /dev tmpfs 1.5G 0 1.5G 0% /dev/shm tmpfs 1.5G 18M 1.5G 2% /run tmpfs 1.5G 0 1.5G 0% /sys/fs/cgroup /dev/mapper/openeuler-root 35G 4.4G 28G 14% / tmpfs 1.5G 64K 1.5G 1% /tmp /dev/vda2 976M 125M 785M 14% /boot /dev/vda1 200M 5.8M 195M 3% /boot/efi tmpfs 298M 0 298M 0% /run/user/0 tmpfs 298M 0 298M 0% /run/user/993 16 Huawei Confidential  Contents 1. Basic Concepts of File Systems 2. Mounting and Using Drive Storage  Drive Basics Drive Partitioning  Formatting and Mounting 3. Logical Volume Management 17 Huawei Confidential Drive Partitioning  Through drive partitioning, a drive is divided into multiple logical storage units called partitions. The system administrator can use different partitions for different functions.  Advantages of drive partitioning:  The available space of applications or users can be restricted.  The machine can boot into multiple OSs from different partitions on the same drive.  OS files are separated from program and user files.  A separate area can be created for OS virtual memory swapping.  Drive space usage can be restricted to improve the performance of diagnosis tools and image backups. 18 Huawei Confidential Drive Partition Types  By partitioning the drive, you are modifying the drive partition table. Pay attention to the following while partitioning:  For the continuity of data, you are advised to place the extended partition in the last cylinders.  A drive has only one extended partition. Except the primary partition space, the rest space is allocated to the extended partition.  Drive capacity = primary partition capacity + extended partition capacity; Extended partition capacity = Sum of the capacities of all logical partitions. Also called primary drive partition. A primary partition cannot Primary be partitioned into other types of partitions. Therefore, each partition primary partition is equivalent to a logical drive. Drive partitions Extended partitions and logical partitions are designed to break Extended the limitation that only 4 partitions can be stored in the partition partition table. An extended partition cannot be directly used. You must partition it as one or more logical partitions. Multiple logical partitions can be created in the extended Logical partition. A logical partition is a continuous area on a disk partition (for HDD) and is a part of the extended partition. 19 Huawei Confidential Drive Partition Naming  There are no drive letters in Linux. You can access a device through the device name. The device names are stored in the /dev directory.  The devices are named as follows: /dev/xxyN xx indicates the device type, which can be hd (IDE drive), sd (SCSI drive), fd (floppy disk drive), or vd (virtio drive). y indicates the device where the partition is located. For example, /dev/hda indicates the first IDE drive, and /dev/sdb indicates the second SCSI drive. N indicates the partition number. The first four partitions (primary partitions or extended partition) are numbered from 1 to 4. The logical partitions start from 5. For example, /dev/hda3 is the third primary partition or extended partition on the first IDE drive, and /dev/sdb6 is the second logical partition on the second SCSI drive.  Note: On Linux, SAS drives, SATA drives, and SSDs are identified by sd, and IDE drives are identified by hd. 20 Huawei Confidential Drive Partitioning Scheme - MBR  Master Boot Record (MBR)  The MBR partitioning scheme specifies how the drive of a system running BIOS is partitioned. The MBR is a special boot sector at the beginning of the drive.  A SCSI drive partitioned using the MBR scheme can have a maximum of 15 partitions, among which a maximum of 4 primary partitions or 12 logical partitions can be created. Extended partitions cannot be directly used and therefore are not counted. An IDE drive partitioned using the MBR scheme can have a maximum of 63 partitions, among which a maximum of 4 primary partitions or 60 logical partitions can be created. Extended partitions cannot be directly used and therefore are not counted.  Because partition size data is stored as 32-bit values, the maximum size of a drive or partition cannot exceed 2 TB when the MBR scheme is used. 21 Huawei Confidential fdisk Drive Partitioning Utility  fdisk is a commonly used traditional Linux drive partitioning utility. fdisk does not support partitions larger than 2 TB.  The command syntax is as follows:  fdisk [options] parameter  Common options are as follows: -b : specifies the size of each partition. -l: lists the partition tables of the specified peripheral devices. -s : prints the specified partition size in sectors to the standard output. -u: used with -l to display the start address of each partition in the unit of sectors instead of cylinders. -v: displays version information. 22 Huawei Confidential fdisk Interactive Mode  Select a drive to enter the interactive mode for drive partitioning.  For example: fdisk /dev/sdb. The following table lists the interactive mode commands. Command Description  The process of creating a primary partition is as follows: a Set a bootable flag. b Edit the BSD disklabel. c Set the DOS compatibility flag. Enter 1 to set Press Enter to d Delete a partition. Enter n to Enter p to the primary set the start Lists known file system types. 82 indicates start create a partition cylinder. l a Linux swap partition, and 83 indicates a partition primary number (the Linux partition. The default creation. partition. number can start cylinder m Displays help menu. be 1 to 4). is cylinder 1. n Create a partition. o Create an empty DOS partition table. p List the partitions. q Quit without saving changes. Enter the end s Creating an empty SUN partition table. Enter w to Enter p to cylinder value t Change the system ID of a partition. save the display or +size to set changes partition u Change the unit of the displayed records. the partition and exit. information. size. v Verify the partition table. w Save and exit. 23 Huawei Confidential fdisk Interactive Mode  The process of creating an extended partition is as follows: Press Enter Press Enter Enter n to Enter e to Enter l to to use the to use the Enter n to start create an create a default remaining create a partition extended logical start space by partition. creation. partition. partition. cylinder. default. Enter the end Enter p to Press Enter Enter w to cylinder display to use the save the value or partition default changes +size to informatio start and exit. set the n. cylinder. partition size.  Note: The extended partition cannot be directly used after creation. You must create a logical partition. 24 Huawei Confidential Drive Partitioning Scheme - GPT  GUID Partition Table (GPT)  As drives continue to increase in capacity, the 2 TB drive and partition size restriction of the old MBR partitioning is no longer a theoretical limit, but an actual problem that is frequently encountered in the production environment. As a result, GPT is replacing the traditional MBR solution for drive partitioning.  GPT assigns a globally unique identifier (GUID) to each partition on a drive. For systems that run Unified Extensible Firmware Interface (UEFI) firmware, GPT is the standard for arranging partition tables on physical drives.  There are no primary or logical partitions with GPT, and each drive can have a maximum of 128 partitions. As GPT uses 64 bits for logical block addresses, a maximum partition size of 18 EB is supported. 25 Huawei Confidential parted Drive Partitioning Utility  parted is a partitioning utility commonly used in Linux to create drive partitions larger than 2 TB. Compared with fdisk, parted is more convenient and enables the partition size to be dynamically adjusted. The command syntax is as follows:  parted [options] [device [command [options...]...]]  The command options are as follows: -h: displays help information. -i: enters the interactive mode. -s: enters the script mode. -v: displays parted version information. device: indicates the drive device name, for example, /dev/sda. command: indicates a parted command. If no command is specified, parted enters the interactive mode. 26 Huawei Confidential parted Interactive Mode  Select a drive to enter the interactive mode for drive partitioning. Command Description Check if partition N satisfies the alignment  For example: parted /dev/sdb. align-check constraint of type min or opt.  The table lists the interactive mode commands. mklabel Create a disklabel (partition table). name Name a specified partition. print Display partition the table or partitions. Create a GPT partition table. GPT is the only option for a rescue Rescue a lost partition. partition size greater than 2 TB. After confirming other Enter mklabel gpt information, run the print command to check whether the resizepart Resize a partition. partition table is in GPT format. rm Delete a partition. Select the device to be edited. By default, only select the specified device is operated. You can change the specified device here. Create a partition. If mkpart is used without Enter mkpart any parameter, parted prompts you to enter disk_set Changes the flag on the selected device. related information step by step. Switch the state of the flag on the selected disk_toggle device. quit Exit. set Change the flag on a partition. Enter q Save the settings toggle Set or unset the flag on a partition. and exit. unit Set the default unit. version Display version information. 27 Huawei Confidential parted Non - Interactive Mode  Configure a selected drive using the non-interactive mode, that is, the command line mode.  For example: parted /dev/sdb Change drive parted /dev/sdb mklabel gpt format to GPT Partition the drive parted /dev/sdb mkpart primary 0 1000 Format the drive mkfs -t ext4 /dev/sdb1 28 Huawei Confidential  Contents 1. Basic Concepts of File Systems 2. Mounting and Using Drive Storage  Drive Basics  Drive Partitioning Formatting and Mounting 3. Logical Volume Management 29 Huawei Confidential Drive Formatting  Formatting involves initializing a drive or a partition in a drive, and formatting a partition into different file systems. This operation usually causes all files in an existing drive or partition to be deleted. View Format the Confirm the 01 supported file 02 drive 03 information types For details about the file types Run mkfs.ext4 /dev/sdb2 to After the formatting is completed, run the supported by Linux, enter mkfs and format the sdb2 partition under ll command to view drive information, for press Tab twice to view commands the root into ext4. example, ll /dev/sdb2. for supported file types. Select a required command to format the drive. 30 Huawei Confidential mkfs Drive Formatting Command  Short for "make file system", mkfs is used to create a Linux file system in a specified partition.  Syntax: mkfs [-V] [-t fstype] [fs-options] filesys [blocks]  The command options are as follows: filesys: the drive partition to be checked. For example, /dev/sda1. -V: produces verbose output. -t: specifies the type of file system. The default value for Linux is ext2. -c: checks the partition for bad blocks before building the file system. -l bad_blocks_file: reads information about bad blocks from the bad_blocks_file file. blocks: specifies the number of blocks to be used. 31 Huawei Confidential Drive Mounting  A formatted drive has to be mounted before you can use it. The reasons are as follows:  Linux adopts "Everything is a file" design. To use the drive, you must set up a link between the drive and a file (directory). The process of setting up a link is called mounting.  When you access the directory linked to the sdb2 drive, you are accessing the sdb2 device file. This directory is equivalent to an entry or interface for accessing sdb2. The drive can be accessed only when this interface is available. Temporary Mounting Permanent Mounting Mount Point Directory The mount /dev/sda5 /test A permanently mounted device The media and mnt directories command mounts /dev/sda5 is automatically mounted when in the root directory are mount to the test directory. The the system is started. Edit the point directories. You can also mounting becomes invalid /etc/fstab file with Vim to create a directory as a mount after the system is restarted. configure permanent point directory. mounting. 32 Huawei Confidential Introduction to fstab  Functions of the /etc/fstab file  This file stores static information about a file system. Upon startup, the OS automatically reads information from the file and mounts the specified file systems to directories accordingly. By writing mounting information to the file, you do not need to manually mount the drives after each startup.  Format of fstab tmpfs /tmp tmpfs nodev,nosuid 0 0 /dev/sda1 / ext4 defaults,noatime 0 1 /dev/sda2 none swap defaults 0 0 33 Huawei Confidential Key Parameters in fstab Field Parameter Function auto Automatically mounts at startup or after the mount -a command is entered. ro Mounts a file system as read-only. rw Mounts a file system as read/write. user Allows any user to mount the file system. nouser Allows only the root user to mount the file system. dev/nodev Does or does not interpret block special devices on the file system. noatime/ Does not update directory inode access records on this file system or directory. nodiratime This option improves the performance. options defaults Uses the default mounting parameters for the file system. sync/async Specifies synchronous/asynchronous I/O. Does or does not honor the SUID and SGID bits. This option is typically used for suid/nosuid certain special tasks so that common users can temporarily escalate their privileges when running programs. Specifies whether to back up the file system (1) or not (0) As most users do not dump 0 /1 install dump, the value of should be set to 0. Sets the fsck check priority for a file system. This value should be set to 1 for pass 0, 1, 2 the root partition and 2 for other devices that need to be checked. 0 indicates that the device will not be checked by fsck. 34 Huawei Confidential  Contents 1. Basic Concepts of File Systems 2. Mounting and Using Drive Storage 3. Logical Volume Management Logical Volume Basics  Managing Logical Volumes  Dynamically Resizing Logical Volumes 35 Huawei Confidential Logical Volume  Logical volume management (LVM) is a mechanism for managing drive partitions in Linux. It is a logical layer built above drives and partitions and below the file systems, which improves the flexibility of drive partition management.  Physical extents (PE): a PE with a unique number is the smallest unit that can be addressed by LVM. The sizes of PEs can be specified, with 4 MB being the default. Once the PE size is determined, it cannot be changed. The PE sizes of all physical volumes in the same volume group are the same.  Logical extents (LE): the minimum storage unit that can be allocated in LVM. The size of LE depends on the size of PE in the volume group (VG) where the logical volume (LV) is located. Within the same VG, the size of the LE is the same as that of the PE. Generally, the LE and PE are in one-to-one correspondence.  Physical volume (PV): an underlying device that provides capacity and stores data. A PV can be an entire drive or a partition on a drive.  Volume group (VG): a VG is created based on PVs and consists of one or more of them. Specifically, PVs are combined to provide capacity allocation. An LVM system can contain one or more VGs.  Logical volume (LV): an LV is created based on a VG. It is a logical device used by end users, and its size can be expanded or reduced. 36 Huawei Confidential Logical Volume Principles  An LV is a large extended partition (VG) consisting of several drive partitions or block devices (PVs). Note that the PVs can be located in different drive partitions and their sizes can be different, and a VG must contain at least one PV. The extended partition cannot be used directly, and the LV can only be used after it is divided into LVs. The LVs can be formatted into different file systems and can be directly used after being mounted. Volume Group(VG) Physical Volume(PV) Physical Volume(PV) PE PE PE...... PE PE PE …... PE PE PE …... PE PE PE Logical Volume(LV) Logical Volume(LV) 37 Huawei Confidential Advantages of Logical Volumes Flexible capacity Easy device naming Advantages of Scalable storage pool Disk striping Logical Volumes Volume mirroring and Online data reallocation snapshotting 38 Huawei Confidential  Contents 1. Basic Concepts of File Systems 2. Mounting and Using Drive Storage 3. Logical Volume Management  Logical Volume Basics Managing Logical Volumes  Dynamically Resizing Logical Volumes 39 Huawei Confidential Process of Creating a Logical Volume LV layer LV 1 LV 2 LV 3 LV 4 LV 5 Use lvcreate to create LVs VG layer VG 1 VG 2 Use vgcreate to combine PVs into physical VGs PV sda1 PV sdb1 PV sdb2 PV sdc1 PV sdc3 PV sdd PV layer Use pvcreate to convert volumes into PVs Partition Partition Partition Partition Partition Partition Physical partition layer sda1 sdb1 sdb2 sdc1 sdc2 sdc3 Use fdisk to format the drives Physical drive layer Drive Drive Drive Drive sda sdb sdc sdd 40 Huawei Confidential Logical Volume Management - Using PVs  The pvcreate command is used to create a PV using a physical drive or drive partition.  Syntax: pvcreate [option] device_file_name  The command options are as follows: -f: forcibly creates a PV without user confirmation. -u: specifies the UUID of the device. -y: answers yes to all questions.  The command parameter is as follows: device_file_name: specifies the device file name for the PV to be created. Note: After a partition is created, the partition ID is 83 by default. You need to change the ID to 8e to create a PV based on the partition. You can run the fdisk command to change the ID. 41 Huawei Confidential Logical Volume Management - PV Usage Example  Create PVs based on drive partitions 6 to 9. Note the use of the braces.  Run the following command: [root@openEuler ~]#pvcreate /dev/hda{6,7,8,9}  Run the pvdisplay, pvscan, or pvs command to view PV information.  For example, run the pvs command: [root@openEuler ~]#pvs # View the general information about the PVs  Output: PV VG fmt Attr PSize PFree /dev/sdb1 vg1000 lvm2 -- 100.00M 100.00M /dev/sdb2 lvm2 -- 101.98M 101.98M 42 Huawei Confidential Logical Volume Management - Using VGs  The vgcreate command is used to create a VG of LVM. A VG combines multiple PVs into a whole, shielding the details of the underlying PVs. When creating an LV on a VG, you do not need to consider the PVs.  Syntax: vgcreate [option] VG_name PV_list  The command options are as follows: -l: specifies the maximum number of LVs that can be created on the VG. -p: specifies the maximum number of PVs that can be added to the VG. -s: specifies the PE size of a PV in the VG.  The command parameter is as follows: VG_name: name of the VG to be created. PV_list: list of PVs to be added to the VG. 43 Huawei Confidential Logical Volume Management - VG Usage Example  Run the vgcreate command to create the vg1000 VG, and then add the /dev/sdb1 and /dev/sdb2 PVs.  Run the following command: [root@openEuler ~]#vgcreate vg1000 /dev/sdb1 /dev/sdb2  Run the vgdisplay or vgscan command to view VG information.  For example, run the vgdisplay command: [root@openEuler ~]#vgdisplay vg1000 Note: If vg1000 is not specified, information about all VGs is displayed. 44 Huawei Confidential Logical Volume Management - Using LVs  The lvcreate command is used to create an LV of LVM. LVs are created on VGs.  Syntax: lvcreate [option] LV_name  The command options are as follows: -L specifies the size of the LV. The unit can be K, M, G, or T (case-insensitive). -l: specifies the size of the LV (number of LEs).  The command parameter is as follows: LV_name: specifies the name of the LV to be created. Note: A created LV has to be formatted and mounted before use. The method is the same as that described in section 2.4. That is, use mkfs to format the LV and use mount to mount the LV to a directory. 45 Huawei Confidential Logical Volume Management - LV Usage Example  Run the lvcreate command to create a 200 MB LV on the vg1000 VG.  Run the following command: [root@openEuler ~]#lvcreate -L 200M vg1000  Run the lvdisplay or lvscan command to view LV information.  For example, run the lvscan command: [root@openEuler ~]#lvscan # Scan all LVs. 46 Huawei Confidential  Contents 1. Basic Concepts of File Systems 2. Mounting and Using Drive Storage 3. Logical Volume Management  Logical Volume Basics  Managing Logical Volumes Dynamically Resizing Logical Volumes 47 Huawei Confidential Expanding Logical Volume Capacity Before capacity expansion, run the vgs command to check 01 whether the VG space is sufficient. Online capacity Run the lvextend - L +SIZE lv_device command to expand expansion 02 the capacity. without unmounting 03 Run the resize2fs device command to resize the file system. 48 Huawei Confidential Reducing Logical Volume Capacity Determine the target size after reduction and ensure that the target LV has 01 sufficient space to store all the original data. Run the umount command to unmount the file system, and run the 02 e2fsck -f command to perform a forcible check. Capacity reduction is risky. Exercise caution. 03 Run the resize2fsdevice command to resize the file system. 04 Run lvreduce to reduce the size of the LV. 05 Mount the file system again. 49 Huawei Confidential Changing Logical Volume Capacity  The lvresize command is used to adjust (increase or decrease) the size of an LV. As the lvresize command provides the lvextend and lvreduce functions, the procedures for expanding and reducing the capacity of an LV are the same.  Syntax: lvresize [option] LV_name  The command options are as follows: -L specifies the size of the LV. The unit can be K, M, G, or T (case-insensitive). -l: specifies the size of the LV (number of LEs).  The command parameter is as follows: LV_name: specifies the name of the LV to be created.  For example, run the lvresize command to increase the capacity: [root@openEuler ~]# lvresize -L +200M /dev/vg1000/lvol0 # Increase the LV space by 200 MB. 50 Huawei Confidential  Quiz 1. (Single-answer) Which of the following commands can be used to format the /dev/hdb6 partition? A. mkfs -t ext4 /dev/hdb6 B. format -t ext4 /dev/hdb6 C. format /dev/hdb6 D. makefile -t ext4 /dev/hdb6 2. (True or false) Because reducing LV capacity is risky, you need to unmount and forcibly check the file system. A. True B. False 51 Huawei Confidential  Summary  This course describes the concept of the file system, how to mount and use drives, and how to manage logical volumes. 52 Huawei Confidential Acronyms Acronym Full Name Description Portable Operating System Interface (POSIX) is the name of a family of related standards specified by the IEEE to define the application programming interface (API), along with POSIX Portable Operating System Interface shell and utilities interfaces for software compatible with variants of the Unix operating system, although the standard can apply to any operating system. GNU (prononunced GAH-noo with a hard "G") is an ambitious project started by Richard GNU GNU's Not Unix Stallman to create a completely free operating system based upon the design of Unix. AT&T American Telephone and Telegraph Co. It was an American telecommunications company founded in 1877 KDE K Desktop Environment One of the popular desktop environments for Linux. Kubuntu uses KDE by default. An interactive command interpreter and a command programming language. 2. A ksh Korn shell command interpreter developed for UNIX, which forms the basis for the z/OS shell. A command line processor for UNIX that provides interactive features such as job control csh C shell and command history. A visual computer environment that represents programs, files, and options with GUI graphical user interface graphical images, such as icons, menus, and dialog boxes, on the screen. A means of communication between a program and its user, based solely on textual CLI command-line interface input and output. 53 Huawei Confidential Thank you. 把数字世界带入每个人、每个家庭、 每个组织，构建万物互联的智能世界。 Bring digital to every person, home, and organization for a fully connected, intelligent world. Copyright© 2023 Huawei Technologies Co., Ltd. All Rights Reserved. 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