# Chapter 6 **Thin provisioning** is a method of optimizing the utilization of available storage by allocating storage space only as it is needed. **Thick provisioning**, also known as fixed or allocated provisioning, involves allocating the full amount of required storage space at the time of provisioning. To get an overview of currently existing devices: ``` lsblk /dev/sdx - SCSI and SATA disks /dev/vdx - KVM virtual machines /dev/nvmexny - is used for NVME devices ``` Naming convention: ``` /dev/sda2 - second partition on the first hard disk /dev/sdb1 - first partition on te second hard disk /dev/nvme0n1p1 - first partition on the first hard disk /dev/nvme0n3p2 - second partition on the third hard disk ``` ## MBR vs GPT ### MBR: * 512 bytes to store boot information * 64 bytes to store partitions * Place for 4 partitions only with max size of 2 TiB * To use more partitions, extended and logical partitions must be used ### GPT * More space to store partitions * used to overcome MBR limitations * 128 partitions maximum ## Creating partitions Common tools: ``` fdisk - creates MBT and GPT partitions gdisk - creates GPT by default parted- can be scripted easily ``` Aliases: ``` linux - standard linux swap - linux swap uefi - uefi boot lvm - logical volume manager ``` Əgər yeni partition yaradarkən fdisk içində `n` əmrindən sonra bu üç yazı çıxırsa bu o deməkdir ki, MBR partition table olunub həmin disk. Çünki 4 free yer var cəmi, extended partition seçimi var və 128 partitionun yaradılması biraz inanılmazdır. ``` [root@localhost ali]# fdisk /dev/nvme0n1 Command (m for help): n Partition type p primary (0 primary, 0 extended, 4 free) e extended (container for logical partitions) All space for primary partitions is in use ``` MBR-dan istifadə edən zaman əgər 3 primary partition varsa bu zaman dördüncünü mütləq extended partition yaratmaq lazımdır ki, LVM-lərdən istifadə edə bilinsin. ## Filesystems ### Comparison of popular filesystems #### XFS is the default filesystem * fast and scalable * uses CoW(copy on write) to guarantee data integrity * size can be increased, not decreased #### Ext4 was default in RHEL6 and still used * backward compatible to Ext2 * uses journal to guarantee data integrity * size can be increased decreased #### vfat offers multi-OS support * used for shared devices #### btrfs is a new and advanced filesystem ### Creating filesystems ``` [root@localhost ali]# mkfs.[Tab][Tab] mkfs.cramfs mkfs.ext2 mkfs.ext3 mkfs.ext4 mkfs.fat mkfs.minix mkfs.msdos mkfs.vfat mkfs.xfs ``` ### mounting filesystems: ``` # Mount command shows all mounted filesystems, including administrative kernel mounts mount # This command mounts vdb1 filesystem into /mnt folder: mount /dev/vdb1 /mnt # You should unmount filesystem before disconnecting a device umount # lsof command will tell you about open files in mount lsof /mnt # findmnt command shows which filesystem is mounted where in the directory structure findmnt ``` #### Example 1 - using fdisk: 1\) Created partition ``` [root@localhost ali]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sr0 11:0 1 12.8G 0 rom /run/media/ali/Rocky-8-9-x86_64-dvd nvme0n1 259:0 0 50G 0 disk ├─nvme0n1p1 259:1 0 1G 0 part /boot └─nvme0n1p2 259:2 0 49G 0 part ├─rl-root 253:0 0 45.1G 0 lvm / └─rl-swap 253:1 0 3.9G 0 lvm [SWAP] nvme0n2 259:3 0 20G 0 disk [root@localhost ali]# fdisk /dev/nvme0n2 Welcome to fdisk (util-linux 2.32.1). Changes will remain in memory only, until you decide to write them. Be careful before using the write command. Command (m for help): n Partition type p primary (0 primary, 0 extended, 4 free) e extended (container for logical partitions) Select (default p): p Partition number (1-4, default 1): 1 First sector (2048-41943039, default 2048): Last sector, +sectors or +size{K,M,G,T,P} (2048-41943039, default 41943039): +2G Created a new partition 1 of type 'Linux' and of size 2 GiB. Command (m for help): w The partition table has been altered. Calling ioctl() to re-read partition table. Syncing disks. ``` 2\) Created filesystem on this partition: ``` [root@localhost ali]# mkfs.xfs /dev/nvme0n2p1 ``` 3\) Mounted the filesystem: As you can see on the last line, mountpoint of /dev/nvme0n2p1 is /mnt ``` [root@localhost ali]# mount /dev/nvme0n2p1 /mnt [root@localhost ali]# [root@localhost ali]# lsblk NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT sr0 11:0 1 12.8G 0 rom /run/media/ali/Rocky-8-9-x86_64-dvd nvme0n1 259:0 0 50G 0 disk ├─nvme0n1p1 259:1 0 1G 0 part /boot └─nvme0n1p2 259:2 0 49G 0 part ├─rl-root 253:0 0 45.1G 0 lvm / └─rl-swap 253:1 0 3.9G 0 lvm [SWAP] nvme0n2 259:3 0 20G 0 disk └─nvme0n2p1 259:4 0 2G 0 part /mnt ``` it is also able to seen in `mount` command: ``` [root@localhost ali]# mount | grep '^/' /dev/mapper/rl-root on / type xfs (rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota) /dev/nvme0n1p1 on /boot type xfs (rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota) /dev/sr0 on /run/media/ali/Rocky-8-9-x86_64-dvd type iso9660 (ro,nosuid,nodev,relatime,nojoliet,check=s,map=n,blocksize=2048,uid=1000,gid=1000,dmode=500,fmode=400,uhelper=udisks2) /dev/nvme0n2p1 on /mnt type xfs (rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota) ``` it can also able to seen in `findmnt` command: ``` [root@localhost ali]# findmnt TARGET SOURCE FSTYPE OPTIONS / /dev/mapper/rl-root xfs rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota <-SNIPPED-> └─/mnt /dev/nvme0n2p1 xfs rw,relatime,seclabel,attr2,inode64,logbufs=8,logbsize=32k,noquota ``` to unmount device: ``` [root@localhost ali]# lsof /mnt lsof: WARNING: can't stat() fuse.gvfsd-fuse file system /run/user/1000/gvfs Output information may be incomplete. [root@localhost ali]# umount /mnt ``` Əgər `wrong fs type` erroru gəlirsə deməli ya filesystem yaratmaq yadımnan çıxıb ya da extended içindəki logical partitionu mount etmək yerinə extended partitionu mount etməyə çalışıram. #### Example 2 - using gdisk: ``` gdisk /dev/nvme0n2 Partition number (1-128, default 1): 1 First sector (34-41943006, default = 2048) or {+-}size{KMGTP}: Last sector (2048-41943006, default = 41943006) or {+-}size{KMGTP}: +2G Current type is 'Linux filesystem' Hex code or GUID (L to show codes, Enter = 8300): 8e00 Changed type of partition to 'Linux LVM' Command (? for help): p Disk /dev/nvme0n2: 41943040 sectors, 20.0 GiB Model: VMware Virtual NVMe Disk Sector size (logical/physical): 512/512 bytes Disk identifier (GUID): C2535E9B-8E81-47F1-8349-81F3BB14DD79 Partition table holds up to 128 entries Main partition table begins at sector 2 and ends at sector 33 First usable sector is 34, last usable sector is 41943006 Partitions will be aligned on 2048-sector boundaries Total free space is 37748669 sectors (18.0 GiB) Number Start (sector) End (sector) Size Code Name 1 2048 4196351 2.0 GiB 8E00 Linux LVM Command (? for help): w Final checks complete. About to write GPT data. THIS WILL OVERWRITE EXISTING PARTITIONS!! Do you want to proceed? (Y/N): y OK; writing new GUID partition table (GPT) to /dev/nvme0n2. The operation has completed successfully. ``` ## /etc/fstab Mountları reboot persistent etmək üçün mountları fstab-a yazmaq lazımdır ``` /dev/sdb1 /data ext4 defaults 0,0 ``` ``` systemd-fstab-generator systemctl deamon-reload ``` `/etc/fstab`da edilən hər hansı səhvə görə sistem normal boot edilməyə bilər. fstab-ın syntaxını doğrulamaq üçün aşağıdakı komandaları icra etmək lazımdır: ``` mount -a # mount olunmamış filesystemləri mount edir findmnt --verify # fstabda error və warning olmamasına baxır ``` Əgər OS açılmasa, grub boot menuda kernel sətri axırındakı aşağıdakı sətirləri silmək lazımdır ki, errorları görək: ``` rhgb quiet ``` reboot etdikdə 1min30san görsədəcək error olan job complete olmağı üçün. Gözlədikdən sonra shell gələcək. fstab-dakı yazdığımız şeylər systemd mount-a tərcümə edilir OS tərəfindən. fstab-dan yaradılmış fayllara aşağıdakı qovluqda baxmaq mümkündür: ``` ls /run/systemd/generator cat /run/systemd/generator/boot.mount ``` Hər hansı mounta bu komanda ilə də baxmaq mümkündür ``` systemctl cat tmp.mount ``` ### systemctl ilə mountun aktivləşdirilməsi ``` # mount komandasında tmp adı keçən sətirləri ekrana yazdıraq [root@localhost ali]# mount | grep tmp devtmpfs on /dev type devtmpfs (rw,nosuid,seclabel,size=1830940k,nr_inodes=457735,mode=755) tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,seclabel) tmpfs on /run type tmpfs (rw,nosuid,nodev,seclabel,mode=755) tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,seclabel,mode=755) tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,seclabel,size=372084k,mode=700,uid=1000,gid=1000) # systemctl vasitəsilə tmp.mount-u aktivləşdirək [root@localhost ali]# systemctl enable --now tmp.mount Created symlink /etc/systemd/system/local-fs.target.wants/tmp.mount → /usr/lib/systemd/system/tmp.mount. # son sətirdə aktivləşdirdiyimiz mountun əlavə edildiyini görürük: [root@localhost ali]# mount | grep tmp devtmpfs on /dev type devtmpfs (rw,nosuid,seclabel,size=1830940k,nr_inodes=457735,mode=755) tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev,seclabel) tmpfs on /run type tmpfs (rw,nosuid,nodev,seclabel,mode=755) tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,seclabel,mode=755) tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,seclabel,size=372084k,mode=700,uid=1000,gid=1000) tmpfs on /tmp type tmpfs (rw,nosuid,nodev,seclabel) # fstab systemctlə çevrildiyi üçün /tmp mountunu fstabda görmək mümkün deyil çünki # heç vaxt burda yazılmamışdı [root@localhost ali]# grep tmp /etc/fstab # tmp.mountun statusuna systemctl əmri vasitəsilə baxırıq: [root@localhost ali]# systemctl status tmp.mount ● tmp.mount - Temporary Directory (/tmp) Loaded: loaded (/usr/lib/systemd/system/tmp.mount; enabled; vendor preset: disabled) Active: active (mounted) since Wed 2024-06-26 10:40:07 +0330; 52s ago Where: /tmp What: tmpfs Docs: man:hier(7) https://www.freedesktop.org/wiki/Software/systemd/APIFileSystems Tasks: 0 (limit: 22886) Memory: 4.0K CGroup: /system.slice/tmp.mount Jun 26 10:40:07 localhost.localdomain systemd[1]: Mounting Temporary Directory (/tmp)... Jun 26 10:40:07 localhost.localdomain systemd[1]: Mounted Temporary Directory (/tmp). ``` ## Persistent naming attributes ``` blkid # shows all devices with their naming attributes tune2fs -L # is used to set a label on an EXT filesystem xfs_admin -L # is used to set a label on an XFS filesystem mkfs.* -L # is used to set a label while creating a filesystem ``` ### XFS UUID clone error Nəyə görə UUİD-ləri istifadə edirik? Əgər 2 partition yaratmışıqsa, məs. /dev/sda5 və /dev/sda6. /etc/fstab içində /dev/sda5-i silsək, əvvəlki /dev/sda6 adını dəyişib /dev/sda5 olacaq çünki ordered numberlə nizamlanır adlar. Bunun qarşısına keçməkçün fstab-da UUİD vermək lazımdır. UUID-lərə bu komanda ilə baxmaq mümkündür: ``` lsblk --fs ``` UUİD vermək qaydası: ``` # bu bizə sda5-in UUID-sini verir blkid | grep sda5 | awk '{ print $2 }' >> /etc/fstab ``` Sonra isə həmin UUID-ni `/etc/fstab` içində yazırıq: ``` UUID="blablabla" /qovluq ext4 defaults 0 0 ``` XFS filesystem clone edildikdə UUID-si də clone olunur. Bu səbəbdən clone edilmiş filesystemə yeni UUID təyin etmək üçün: ``` xfs_admin -U generate /dev/sdb1 ``` ## parted ``` [root@localhost ali]# parted /dev/nvme0n2 unit GiB print Model: NVMe Device (nvme) Disk /dev/nvme0n2: 20.0GiB Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags: Number Start End Size Type File system Flags 1 0.00GiB 2.00GiB 2.00GiB primary xfs ``` Parted vasitəsilə disk-in partition table-nı GPT-yə çevirmək üçün: {% hint style="danger" %} Əgər diskdə data varsa bu əmrlər həmin dataları siləcək {% endhint %} ``` parted /dev/nvme0n2 mklabel gpt ``` MBR-a çevirmək üçün: ``` parted /dev/nvme0n2 mklabel msdos ``` ### diskə partition table verilməsi və partition yaradılması Bu komanda `/dev/nvme0n2` diskini GPT-yə çevirir, `userdata` adlı partition yaradır, filesystemi `xfs` edir, və ölçünü 1000MB təyin edir: ``` parted /dev/nvme0n2 mklabel gpt mkpart usersdata xfs 2048s 1000MB ``` Bu komanda `/dev/nvme0n2` diskini MBR-a çevirir, primary partition yaradır, filesystemi xfs edir, və ölçünü 1000MB edir: ``` parted /dev/nvme0n2 mklabel msdos mkpart primary xfs 2048s 1000MB ``` Həmin komanda interaktiv formada da icra edilə bilər: ``` [root@localhost ali]# parted /dev/nvme0n2 GNU Parted 3.2 Using /dev/nvme0n2 Welcome to GNU Parted! Type 'help' to view a list of commands. (parted) (parted) mklabel msdos Warning: The existing disk label on /dev/nvme0n2 will be destroyed and all data on this disk will be lost. Do you want to continue? Yes/No? yes (parted) (parted) mkpart Partition type? primary/extended? primary File system type? [ext2]? xfs Start? 2048s End? 3GiB (parted) (parted) print Model: NVMe Device (nvme) Disk /dev/nvme0n2: 21.5GB Sector size (logical/physical): 512B/512B Partition Table: msdos Disk Flags: Number Start End Size Type File system Flags 1 1049kB 3221MB 3220MB primary xfs lba (parted) quit Information: You may need to update /etc/fstab. [root@localhost ali]# [root@localhost ali]# udevadm settle ``` Bu komanda sistemin yeni partitionu detect edib həmin partitionu `/dev` qovluğunda yaratmasını gözləyir: ``` udevadm settle ``` ## SWAP partition --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://alicenab.gitbook.io/linux/redhat/redhat-administration-2-rh134/chapter-6.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.