Flushing DNS Cache on your system.
When your computer visits a website for the first time, it stores the website’s DNS information in a local cache.
The instructions unique to particular operating systems are below.
From the command line on a windows operating system type:
From a Linux operating system.
Nscd is a daemon that provides a cache for the most common name service requests
From MAC on the terminal window
Directory Service (DNS) cache - Gather information, statistics, initiate queries, flush the cache. dscacheutil replaces most of the functionality of thelookupd tool provided prior to OS X Leopard.
Scanning Disks for Volume Groups to Build the Cache File
The vgscan command scans all supported disk devices in the system looking for LVM physical volumes and volume groups. This builds the LVM cache in the /etc/lvm/.cache file, which maintains a listing of current LVM devices.
LVM runs the vgscan command automatically at system startup and at other times during LVM operation, such as when you execute a vgcreate command or when LVM detects an inconsistency. You may need to run the vgscan command manually when you change your hardware configuration, causing new devices to be visible to the system that were not present at system bootup. This may be necessary, for example, when you add new disks to the system on a SAN or hotplug a new disk that has been labeled as a physical volume.
You can define a filter in the lvm.conf file to restrict the scan to avoid specific devices.
SYNOPSIS
DESCRIPTION
lvm.conf is loaded during the initialisation phase of lvm (8). This file can in turn lead to other files being loaded - settings read in later override earlier settings. File timestamps are checked between commands and if any have changed, all the files are reloaded.
Use lvm dumpconfig to check what settings are in use.
# lvm dumpconfig
devices {
dir=”/dev”
scan=”/dev”
preferred_names=[]
filter=”a/.*/”
cache_dir=”/etc/lvm/cache”
cache_file_prefix=”"
write_cache_state=1
sysfs_scan=1
md_component_detection=1
ignore_suspended_devices=0
}
