shukko.com v.x3

MySQL Repair and Optimize All DB

shukko — Tue, 15 May 2012 02:31:13 +0000

mysqlcheck -u da_admin -p --auto-repair --optimize --all-databases


veya

mysqlcheck -Aor -u root -p A = all databases o = optimize r = repair

use nano as crontab editor

shukko — Thu, 10 May 2012 11:10:50 +0000

This is a small tip, I like to use, as normally in recently installed Linux, vi is used as the default editor instead of vim or nano.

So, How to change the default crontab editor to vim or nano?

To change to vim or nano just run:

export EDITOR="/usr/bin/vim" ; crontab -e

that is for vim, or.

export EDITOR="/usr/bin/nano" ; crontab -e

OK, you are now ready to work with your favorite text editor, instead of the default.

Server Support: Dealing with Downtime

shukko — Wed, 09 May 2012 20:34:48 +0000

TR NOT: bu asagidaki yazi yillardir ugrastigim herseyi kisaca ve ozce cok guzel anlatmis.

belki bir gun Turkceye ceviririm. Orjinal link pingzineden en asagida linki.

You get a call at 2 am in the morning. One of your servers with over 1000 shared accounts on them has gone down. You rush to the office (thank God it’s close to home) and find your support staff frantically working on the server and at the same time trying to field calls and emails from irate customers. After several tense moments, the cause is found. The load is very high, causing services to fail. Your support staff suggests a reboot instead of diagnosing the reason for high load. You say ok, go ahead, as long as the load comes back to normal and all services run normally. Reboot done, and the team spends the rest of the night replying to customers. Later, you have no clue why the load went up the way it did because there were no logs.

Downtime is serious. In this age of social networking on Twitter and Facebook, bad news flies really fast. This kind of negative publicity can seriously result in loss of reputation and customers within a single day. It’s no wonder, Hosts have to be on top of their business all day every day.

Downtime is a reality in the Hosting business. Do the math. Here are some commonly advertised service availability figures.

99.9% availability equates to 8 hours and 45 minutes of downtime per year.
99.99% availability equates to around 52 minutes of downtime per year.

Even the most reliable WebHost has 52 minutes of downtime in a year. This downtime can be a result of scheduled or unscheduled events or both. In this article, we will look at ways to deal with both types of events.

Dealing with scheduled downtime

Scheduled downtimes are a necessary part of server maintenance. A web host who regularly maintains the servers will reduce incidence of security vulnerabilities, increase performance and improve customer experience. A good host will have more scheduled downtimes than unscheduled downtimes.

The most important way of dealing with scheduled downtime is through “Proactive Communication”. In this type of communication, you let customers know about the downtime before they find out on their own. Sounds simple, isn’t it. The sad fact is that many Hosts do not follow it well enough. So lets see how this helps.

How does proactive communication help?

Proactive communication is a very useful method for customer retention during downtimes.

Gives you time to let your customers know all the great benefits they can hope to get with the changes in the system.
Reduces customer confusion
Helps customers inform their customers of downtime
Reduce flood of tickets during the downtime
Customers appreciate that you let them in on your plans.

How to setup proactive communication

Before shooting all your customers an email, spend a few minutes deciding what you will tell them. A nicely formatted and complete email will reduce a lot of confusion and reduce the burden on your support team, especially when they are busy with the maintenance work. Here are some pointers.

What to tell your customers during scheduled downtime. Tell them…

When the maintenance is scheduled (Exact date and time)
How long maintenance will last (down to the minutes)
What exactly will get disrupted (eg, web, mail etc)
Reasons for maintenance
Benefits to the customer once the maintenance is done
How to contact support staff during maintenance (via email, forum etc)
Alternative arrangements they can do, if any.

When to tell them

At least one week prior to the event.
Again, 24 hours before the event

How to tell them

News section on website
Email
Social media (Twitter, Facebook)
Forum or blog

Dealing with Unscheduled downtime

Unscheduled downtimes happen when something unexpected or untoward happens. The reasons for unscheduled downtimes could include sudden increases in traffic, hacking attempts, old software leading to exploited vulnerabilities, DOS attacks, spam resulting in flooding of the queues, even the occasional hardware failure. No wonder it is a nightmarish scenario to deal with at 2am in the morning.

So what can hosts do to prevent a massive downturn, in the event of a downtime? Simply follow the 2Ps.

Prevent downtime
Prepare for downtime

How to Prevent downtime

Wouldn’t you service your car periodically to prevent breakdowns and expensive repairs. The same way, a server is the engine on which your hosting business runs. An important way to prevent downtime is to maintain your server hardware and software periodically. This type of server administration is called Proactive server administration.

In proactive server administration, always start by first securing the server with at least these steps. Note that these methods should be performed by a trained professional.

Make sure the software is all updated
Configure a firewall and restrict access to critical ports
Decide on minimum services and secure those services. Close unwanted services.
If you have shared accounts, check user security such as weak passwords.
Enable extended logging so that detecting during disaster is easier.
Secure world writable directories.

Monitor availability of servers and individual services. For example, if your server load frequently goes high, you should be able to set up notifications that inform you of cut off load long before it becomes dangerously high. This helps you prevent downtime simply by checking on it, before the load creeps up and brings the server down.

It is always useful to log all information for critical services, and to set up notifications for certain events. This helps in debugging and preventing future downtimes. The scenario I presented in the beginning, could have been prevented if logs were maintained.

Keep track of exploits and service vulnerabilities. Sites like secunia.org and milw0rm.com have newsletters and mailing lists that you can sign on, thats gives you information first hand on any vulnerabilities. Take action before hackers do.

Also, always conduct a monthly server audit to check for any suspect logins, spamming, server performance etc.

How to prepare for downtime

The first step to prepare for downtime is to visualize your reaction if an unscheduled downtime took place.

How would you contact your customers? Is your infrastructure up to speed to deal with an emergency. For example a helpdesk system, your website, phone lines and email are critical systems that should be available to engage with your customers in times of downtime.

Some people wonder whether to communicate unscheduled downtime to customers. The downtime is going to last a few minutes. Should the host inform customers of unscheduled downtime?

And the answer is Yes!! The worst thing the host wants to do is to have customers find out by themselves, or worse, their customers. By being responsible and letting customers know, you seem to be on top of your business. Customers appreciate the fact that you informed them, rather than the other way around.

Always prepare to send a lightening response to customers who are experiencing downtime. Here are a few things you should prepare.

Speed of response. You need to put up information on your website within minutes of the downtime at least.
Decide where you are going to put up this information on the website. How you are going to contact your customers.
Many times you need professional help in solving downtime issues. Form those relationships early on, so that they are available when you need them.
If you have an in-house team, make sure they are ready and knowledgeable to solve these issues when they happen.

By prevention and careful preparedness, you can avoid downtimes taking a hit at your business and your customers’ businesses.

TAKEN FROM: http://www.pingzine.com/server-support-dealing-with-downtime-2/

Migrating large sparse files over the network

shukko — Sat, 21 Apr 2012 08:29:54 +0000

Original link: http://lathama.net/Migrating_large_sparse_files_over_the_network

Migrating large sparse files over the network

Intro

When you need to move large sparse files across the network there are many issues related to support of this new FS method. Sparse files are files that say they are size X but only allocate blocks on the file system that are actually used. This is a great use of space and very nice for virtualization. In the past methods like COW to only use space as it was needed. These solutions worked. Sparse file support was integrated into the Linux Kernel and now it is the preferred way to handle images.

Problem

The need to move a large 100GB+ file from one server to another over the network. The file is sparse in nature which means that only a small portion of the file may actually be used. One does not want to transfer every byte of data and to fully allocate the file on the target system.

Solution

Use Tar with its support for Sparse and stdin and stdout. Tar checks the source file twice (normally and a second time for sparse) before streaming. On large files this can take time and processing power. The target file will be checked as it is written.

Requirements

Pipe Viewer will show us what is happening in the pipe. Without this you may go insane.

serverA:/# aptitude install pv
serverB:/# aptitude install pv

First you need to understand that Tar is going to look at the file TWICE. This will take lots of time and make you think nothing is happening. Wait, Wait, Wait and then smile. Select a port under 45,000 and above 1024 that is not in use by another service.

Example*

serverA:/# tar -cS IMG.img | pv -b | nc -n -q 15 172.20.2.3 5555
serverB:/# nc -n -l 5555 | pv -b | tar -xS

As an example here is another method. As with all SSH connections, it will cause 99% + CPU load for the duration of the connection even with compression off.

tar -cS IMG.img | pv -b | ssh -o 'Compression no' root@172.20.2.3 "cat > IMG.img.tar"

Then you need to extract the TAR image.

tar -xSf IMG.img.tar

Summary

There are other methods of completing this action. This method is the fastest that I have found. Using Rsync with Sparse options does work but it trasfers every null byte over the network, so it takes more time. It also runs two checksums on both source and target files. Further testing shows that compression can cause issues if one or both the servers are under load. This method can also be used over SSH or other authenticated protocols.

* This method has only hung once for me. If it causes you issues, wait for the connection to time out or test with another image.

A Bash Shell Script to do Multiple Whois Lookups

shukko — Fri, 06 Apr 2012 19:40:40 +0000


#!/bin/bash

for domain in `cat domains.txt`

do

   echo $domain

   `whois $domain >> whois-results.txt`

done

Installing vzdump for OpenVZ on Centos

shukko — Mon, 02 Apr 2012 23:01:02 +0000

Here is how you get vzdump on a clean version of CentOS (via the hostnode):
rpm -ivh "ftp://ftp.pbone.net/mirror/ftp.freshrpms.net/pub/freshrpms/pub/dag/redhat/el5/en/x86_64/RPMS.dag/cstream-2.7.4-3.el5.rf.x86_64.rpm" wget http://dag.wieers.com/rpm/packages/perl-LockFile-Simple/perl-LockFile-Simple-0.206-1.el5.rf.noarch.rpm rpm -ivh perl-LockFile-Simple-0.206-1.el5.rf.noarch.rpm /bin/rm perl-LockFile-Simple-0.206-1.el5.rf.noarch.rpm rpm -ivh "http://chrisschuld.com/centos54/vzdump-1.2-6.noarch.rpm"
Since version 1.2-6 of vzdump the location of the modules is not “automatic” and have found it necessary to export the location of the PVE libraries that vzdump requires via this command:
export PERL5LIB=/usr/share/perl5/

DONE!

vzdump , vzrestore …

———-

ONEMLI NOT:
YUKARIDAKILER CENTOS5 ICIN CALISIYOR
CENTOS 6.2 DE YAPTIGIMDA CORBA OLDU HERSEY
SU SEKILDE YAPILMASI GEREK CENTOS 6.2 DE

cd /tmp
wget http://pkgs.repoforge.org/cstream/cstream-2.7.4-3.el6.rf.i686.rpm
wget http://pkgs.repoforge.org/perl-LockFile-Simple/perl-LockFile-Simple-0.207-1.el6.rf.noarch.rpm
rpm -ivh cstream-2.7.4-3.el6.rf.i686.rpm
rpm -ivh perl-LockFile-Simple-0.207-1.el6.rf.noarch.rpm

rpm -ivh http://download.openvz.org/contrib/utils/vzdump/vzdump-1.2-4.noarch.rpm

DEBIAN: How-to install secure pure ftp server chrooted with virtual users

shukko — Sun, 01 Apr 2012 01:55:09 +0000

aptitude install pure-ftpd nano /etc/pure-ftpd.conf --------- ChrootEveryone yes BrokenClientsCompatibility no MaxClientsNumber 10 Daemonize yes MaxClientsPerIP 5 VerboseLog no DisplayDotFiles no AnonymousOnly no NoAnonymous yes SyslogFacility ftp DontResolve yes MaxIdleTime 15 PureDB /etc/pureftpd.pdb LimitRecursion 2000 8 AnonymousCanCreateDirs no MaxLoad 4 UserRatio 5 10 AntiWarez no UserBandwidth 200 Umask 133:022 MinUID 100 AllowUserFXP no AllowAnonymousFXP no ProhibitDotFilesWrite yes ProhibitDotFilesRead yes AutoRename no AnonymousCantUpload yes AltLog stats:/var/log/pureftpd.log NoChmod yes CreateHomeDir yes Quota 2000:500 MaxDiskUsage 80 CustomerProof yes PerUserLimits 3:20 IPV4Only yes ------------ nano /etc/default/pure-ftpd-common >> STANDALONE_OR_INETD=standalone , VIRTUALCHROOT=true


nano /etc/pure-ftpd/conf/PureDB       >>     /etc/pure-ftpd/pureftpd.pdb
cd /etc/pure-ftpd/auth
ln -s /etc/pure-ftpd/conf/PureDB 50pure
sudo groupadd ftpgroup
sudo useradd -g ftpgroup -d /dev/null -s /etc ftpuser
Create our first virtual user
pure-pw useradd joe -u ftpuser -g ftpgroup -d /home/pubftp/joe
We will have to type his password twice, and we are almost ready to go.
Save the password file, I mean create the pure-ftp password database run this command:
pure-pw mkdb
Do this each time you make changes to the password file.
/etc/init.d/pure-ftpd start
Some other tips
    To list users
    pure-pw list

    To see some user's information
    pure-pw show joe

    Where joe is the user you want to list his info.

    To change a password
    pure-pw passwd joe

    Be sure to update the database by running:
    pure-pw mkdb

Free Public DNS Servers

shukko — Thu, 29 Mar 2012 20:31:55 +0000

Free Public DNS Servers

=> Service provider: Google
Google public dns server IP address:
8.8.8.8
8.8.4.4

=> Service provider:Dnsadvantage
Dnsadvantage free dns server list:
156.154.70.1
156.154.71.1

=> Service provider:OpenDNS
OpenDNS free dns server list / IP address:
208.67.222.222
208.67.220.220

=> Service provider:Norton
Norton free dns server list / IP address:
198.153.192.1
198.153.194.1

=> Service provider: GTEI DNS (now Verizon)
Public Name server IP address:
4.2.2.1
4.2.2.2
4.2.2.3
4.2.2.4
4.2.2.5
4.2.2.6

=> Service provider: ScrubIt
Public dns server address:
67.138.54.100
207.225.209.66

hp ilo port listesi

shukko — Thu, 22 Mar 2012 16:35:17 +0000

If you want to access an iLO behind a firewall, there are some TCP ports that need to be opened on the firewall to allow all iLO traffic to flow through. Here is a list of the default ports used by iLO, but these can be modified on iLO’s Administration… Access… Services… tab.

ILO FUNCTION SOCKET TYPE PORT NUMBER
———————- ———– ———–
Secure Shell (SSH) TCP 22
Remote Console/Telnet TCP 23
Web Server Non-SSL TCP 80
Web Server SSL TCP 443
Terminal Services TCP 3389
Virtual Media TCP 17988
Shared Remote Console TCP 9300
Console Replay TCP 17990
Raw Serial Data TCP 3002

mytop

shukko — Wed, 21 Mar 2012 15:44:45 +0000

perl -MCPAN -eshell


install Term::ReadKey

install DBD::mysql

exit