163 lines
3.1 KiB
Markdown
163 lines
3.1 KiB
Markdown
---
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title: "partitions"
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tags: [ "Documentation", "system" ]
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---
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# FDisk Basics
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> sudo fdisk /dev/sda
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- m for help.
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- n to make a partition.
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- t to mark the partition type (see IDs below).
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- w to write the changes to the disk.
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Note the asterisk marking the boot partition.
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# IDs
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| ID | Meaning |
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|----|:--------|
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|83 |Linux |
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| 5 |Extended |
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| 82 |Swap |
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fdisk will not help with a GPT formatted drive. For this, use gdisk, which is mostly the same.
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Now that we have a partition, we can make it into a filesystem. Most will use:
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> sudo mkfs -t ext4 /dev/sdc1
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or if you're making a swap partition, you can use:
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> sudo mkswap /dev/sdb2
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or for the reiser filesystem, we can use:
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> sudo mkreiserfs /dev/sdc2
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# File System Types
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| Type | Advantages | Disadvantages |
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|------|:-----------|:--------------|
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|ext2 | |No journaling means that the file offers no crash recovery.
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|ext3 | Journaling |
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|ext4 | Journaling and handles files of up to 16TB.|
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|reiserfs| Journalin and stable.|
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|btrfs |Reliable and stable|
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|XFS |Journaling, great for large files.|
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|VFAT |Comptable with Windows, like FAT32|
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# Parted
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> sudo parted /dev/sdb
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# Monitoring
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Look at physical and virtual partitions:
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> df -h
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or divide things by inode - the thing which records where files are?
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> df -i
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Examine a filesystem with:
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> sudo dumpe2fs /dev/sda1 | less
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# Prevention
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There are multiple programs which work mostly the same way.
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> sudo tune2fs -c 30 /dev/sda1
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This will check sda1 every 30 boots. It can also be checked every month.
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> sudo tune2fs -i 1m /dev/sda1
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This thing can also make a new label for the system:
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> sudo tune2fs -L new_name /dev/sdb3
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# Repair
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Start by unmounting the filesystem.
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> sudo umount /dev/sdc1
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Then it's time to check.
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> sudo fsck /dev/sdc1
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And possibly repair damage:
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> e2fsck -p /dev/sdc1
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or the same with:
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> sudo debugfs /dev/sdc1
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# Mounting
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You can mount with a specified filetype with:
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> sudo mount -t ext3 /dev/sdc2 /mnt/stick
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or if you don't know the type, just try the lot:
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> sudo mount -a /dev/sdc1 /mnt/stick
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# File Systems
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xfs and zfs can only be expanded.
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# Shrink Filesystem
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NB: When I followed these instructions, the process destroyed my data. Seemed fine on the YouTube video.
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Check the filesystem's health:
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> sudo e2fsck -f /dev/sdb1
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Resize the file system to something smaller than what you want, so here I want 500G and so I resize to 450 G.
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> resize2fs /dev/sdb1 450G
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Then delete the partition with either gdisk or fdisk, depending upon the layout.
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> sudo fdisk /dev/sdb
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> d
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Then make a new filesystem of the desired type with:
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> n
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And finally resize to the full size you want:
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sudo resize2fs /dev/sdb1
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And then check your disk again with e2fsck.
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(The e2fsck saved my disk in the end, YMMV)
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# Logical Volume
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Let's start with names. PV = 'Physical Volume', VG = 'Volume Group', and LV = 'Logical Volume'.
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Now we can create a volume group out of sdb2 and sdc3:
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> sudo vgcreate my-new-vg /dev/sdb2 /dev/sdc3
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Then make a new logical volume out of the volume group:
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> sudo lvcreate -n my-new-lv my-new-vg
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Then have a look at all logical volumes:
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> sudo lvscan
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