Some hosts (eg OVH) customize the kernel of the linux os they provide. Heres how to fix it.
sudo apt-get install linux-image-server mv /etc/grub.d/06_OVHkernel /etc/grub.d/25_OVHkernel update-grub shutdown -r now
Notes on /etc/grub.d
Grub = GNU GRand Unified Bootloader. Allows selection of multiple operating system on boot, or specific kernel configurations. Files in that dir listed alphabetically form the boot order. the mv command moves ovh's custom kernal to a lower level which means that another kernal will be used in its place.
originally retrieved from: https://www.digitalocean.com/community/tutorials/how-to-add-swap-on-ubuntu-12-04
But essentially it goes like this:
Create the swap file itself:
sudo dd if=/dev/zero of=/swapfile bs=1024 count=1024k
The swap file will be initially filled with zeros (0s). The file will be created at /swapfile. bs specifies the block size in bytes. A block is a unit measuring the number of bytes that are read, written, or converted at one time. count specifies how many blocks. Here creating a file made up of 1024k blocks, each having a size of 1024 creates a 1 Gb file.
Creating a linux swap area
sudo mkswap /swapfile
Activating the swap file
sudo swapon /swapfile
Automount this on reboot
sudo nano /etc/fstab /swapfile none swap sw 0 0
Check summary of swap usage
Check memory usage to confirm swap is usable.
Where my disk space gone?
If the new volume has never been formatted, you need to format the volume using mkfs before you can mount it.
For instance, the following command creates an ext4 file system on the volume:
~# mkfs -t ext4 /dev/nbd1
which then can be mounted by say...
mkdir -p /mnt/data mount /dev/vdb /mnt/data ls -la /mnt/data/
/etc/fstab: /dev/vdb /mnt/data auto defaults,nobootwait,errors=remount-ro 0 2
(not sure if working)
tmpfs / ram disk
how to make a temp fs?? ..
mkdir -p /var/tmpfs sudo mount -t tmpfs -o size=512M tmpfs var/tmpfs
disk speed test
sudo hdparm -Tt /dev/sda
dd if=/dev/zero of=/tmp/output bs=8k count=10k; rm -f /tmp/output