When you do an SSH or SCP to a server, you may find the below error message.
“SSH returns: no macthing key type found. Their offer ssh-rsa,ssh-dss”.
You can add the -oHostKeyAlgorithms option to access the server. For example.
ssh -oHostKeyAlgorithms=+ssh-dss admin@yogindar.com
Source: SSH returns: no matching host key type found. Their offer: ssh-dss – Ask Ubuntu
Nice matrix on Oracle Linux and UEK version support. Also a nice article who follows Oracle Linux versions and its support details.
Source: Oracle Linux and Unbreakable Enterprise Kernel (UEK) Releases
Reference for Linux ERROR CODE TABLE.
Source: 131 Linux Error Codes for C Programming Language using errno
Nice tutorial on Linux kernel.
Nice reference on how to create swap space on an SD card.
vm.min_free_kbytes setting allows kernel to compute a minimum value in the low memmory zone and reserve it for its own use.
To read the current value
[Fri Mar 24 15:18:05 root@system:~]$sysctl vm.min_free_kbytes
vm.min_free_kbytes = 1888
To set new value of 4MB. Based on your system requirement configure the value. Ideally 1.8% is good enough.
echo 4096 > /proc/sys/vm/min_free_kbytes
To configure permenantly on every reboot add the below entry to /etc/sysctl.conf
vm.min_free_kbytes=4096
Some basics on Linux Software RAID. There are good references on the same in the same wiki.