ethtool: offloading
Enable stateless offloads to improve system performance.
Stateless offloads, such as checksum offload, segmentation offload, and large receive offload, can improve system performance by moving some of the processor-intensive tasks that do not require a connection to the network adapter.
Recovering deleted lvm volume
LVM is a logical volume manager for the Linux kernel; it manages disk drives and similar mass-storage devices, in particular large ones. The term "volume" refers to a disk drive or partition thereof.
Every LVM operation makes backup of lvm metadata. Metadata archive stored in directory /etc/lvm/archive/ in easily readable text files. Each operation creates own metadata backup file, with information when it was created. For example:
Still using debian etch?
When you need install some package to old discontinued debian, you will get
Error 404 Not FoundSolution is change /etc/apt/sources.list
deb http://archive.debian.org/debian/ etch main non-free contribSource http://linuxsysadminblog.com/2010/07/debian-ftp-archive-for-etch-archive-debian-org/
Checking forward and reverse dns
Very often problems like 'my website is not working' or 'I did not get any emails' are caused by improperly set up dns records or expired domain. At my work, I'm permanently dealing with incorrectly set up dns records. There are available services like intodns.com which you can use to check dns records for domain. But what to do, if you have problem with reverse dns? Or you want to check, if your reverse delegation is set up correctly?
Hardware raid in debian
To manage and monitor hardware raid, you need proper utility. Most of vendors provides raid utilities only for Redhat based linuxes. For Debian based distribution I have found very useful repository - http://hwraid.le-vert.net/wiki/DebianPackages. You just need to know, which raid card you are using and follow provided instructions.