Partitions
gparted, cfdisk, lsblk, df -h
mkfs.ext4 /dev/sda2 , mkfs.ntfs etc --- format the partition
sudo fdisk -l --- view disks
lsblk -f --- view disks and filesystems
sudo blkid - partition UUID
df -h
df -ih --- innodes
sudo tune2fs -l /dev/sda8
sudo tune2fs -m 1 /dev/sda8
Reserved blocks for root - so when you run out of space you can still login. Set default to 5% of partition size..
*** merge online cu partitia mounted = ok
After you rezise partition size with cfdisk you need to also resize the filesystem:
sudo resize2fs /dev/sdb
Mounting
/mnt : Mount point for a temporarily mounted filesystem - should not have subfolders
/media : Mount point for removeable media
These 3 are required for chroot,
are interfaces to kernel data structures and not real files on hdd - they stay in ram.
Can check with the command findmnt /sys
/dev - file devices
/proc - running process table + some system info same as sys left for backward compatibility
/sys - hardware information
/run - virtual ram runtime for udev - needed before /var/run is mounted
/etc - system config files - before changes would be done in source code and recompile
means etcetera - as in the rest of the files of a system
/var - variable stuff like logs
/opt - optional software not installed with system package manager
/usr - libraries, binaries, manuals - all the software
/etc/fstab --- automount at start-up - should at least have /
mount -a --- mount all from fstab
UUID=14D82C19D82BF81E /mnt/d auto nosuid,nodev,nofail,x-gvfs-show 0 0
1. partition id
2. mount point
3. partition type
4. options
nosuid - specifies that the filesystem cannot contain set userid files. This prevents root escalation and other security issues.
nodev - specifies that the filesystem cannot contain special devices (to prevent access to random device hardware).
nofail - removes the errorcheck.
x-gvfs-show - show the mount option in the file manager. If this is on a GUI-less server, this option won't be necessary.
0 - determines which filesystems need to be dumped (0 is the default).
0 - determine the order in which filesystem checks are done at boot time (0 is the default).
mount /dev/sda1 /mnt
NTFS partition from windows closed without proper shutdown ---> ntfsfix /dev/sda1
If that doesn't work you need to boot a windows os and it will fix it. ntfs is not opensource.
See mounted filesystems and space usage :
du -sh -- file/folder size
The file system has an inode table - every file and directory on a disk requires one inode entry.
To have more inode you need to re-format the filesystem and reserve more space for the inode table.
Other filesystems dont allocate a fixed inode table like XFS, JFS, BtrFS or ZFS.
On ext3 and ext4 - the most common used filesystems on linux you get by default 1 inode for every 16kb of space.
using the -i flag to mkfs.ext4 to specify the bytes:inode ratio.
This problem is most common on servers where you can get a lot of small files.
Apache’s disk cache system (mod_cache_disk) - creates a lot of small files - htcacheclean should clean it.
Swap
Instead of storage swap partition you can have a swap partition in ram.
Of course this will not work for hibernation.
Swap file
dd if=/dev/zero of=/swapfile bs=1M count=3064 status=progress
chmod 600 /swapfile
mkswap -U clear /swapfile
swapon /swapfile
Add it to fstab
/swapfile none swap defaults 0 0 >> /etc/fstab
Ram swap
When ram gets full, data is moved and compressed into this z swap partition.
To enable it, open a cmd and create these files :
sudo su
echo zram > /etc/modules-load.d/zram.conf
echo 'options zram num_devices=1' > /etc/modprobe.d/zram.conf
echo 'KERNEL=="zram0", ATTR{disksize}="512M",TAG+="systemd"' > /etc/udev/rules.d/99-zram.rules
touch /etc/systemd/system/zram.service
[Unit]
Description=Swap with zram
After=multi-user.target
[Service]
Type=oneshot
RemainAfterExit=true
ExecStartPre=/sbin/mkswap /dev/zram0
ExecStart=/sbin/swapon /dev/zram0
ExecStop=/sbin/swapoff /dev/zram0
[Install]
WantedBy=multi-user.target
sudo systemctl enable zram
reboot
swapiness - sudo nano /etc/sysctl.conf
The default value is 60."
0 - does not disable swap
To use a swap partition instead
# mkswap /dev/sda5
# sync
# swapon /dev/sda5
Ram-disk
For windows :The only free software that allows for more then 4gb is
ImDisk ToolkitFor linux :
First check how much ram you got :
free -h
Make a new directory and mount the ramdisk :
sudo mkdir /mnt/ramdisksudo mount -t tmpfs -o size=10g tmpfs /mnt/ramdisktmpfs - is mounted in ram
To make it available every time you boot edit /etc/fstab :
tmpfs /mnt/ramdisk tmpfs nodev,nosuid,noexec,nodiratime,size=1024M 0 0
