http://www.randombugs.com Just another Bastard Operator From Hell. Everything from *nix to programming Thu, 06 May 2010 14:21:46 +0000 en hourly 1 http://wordpress.org/?v=3.0 http://www.randombugs.com/linux/compile-configure-modqos-prevent-slowloris-ddos-apache-2-debian-lenny-distribution.html http://www.randombugs.com/linux/compile-configure-modqos-prevent-slowloris-ddos-apache-2-debian-lenny-distribution.html#comments Tue, 04 May 2010 20:00:13 +0000 admin http://www.randombugs.com/?p=650
mod_qos is becoming a very popular module for Apache, from the discover of Slowloris DDoS Attack. It seems, mod_qos is the best solution for Slowloris attack on Apache 2, but you can also check mod_evasive, mod_security or http accelerator “Varnish”. In this post I will try to present a step by step tutorial how to install mod_qos and configure to prevent Slowloris DDoS attack. This post is just a compendium of other good posts: How To Defend slowloris DDoS With mod_qos (Apache2 On Debian [Lenny]) DDoS, Apache2 and mod_qos How to best defend ...]]> http://www.randombugs.com/linux/compile-configure-modqos-prevent-slowloris-ddos-apache-2-debian-lenny-distribution.html/feed 0 http://www.randombugs.com/java/glassfish/glassfish-cluster-211-httpsessions-replication-multithread-concurrent-access.html http://www.randombugs.com/java/glassfish/glassfish-cluster-211-httpsessions-replication-multithread-concurrent-access.html#comments Wed, 03 Mar 2010 10:07:06 +0000 admin http://www.randombugs.com/?p=634
I have several clusters with Glassfish 2.1.1 in a BIG virtual environment and all worked fine … until I add new processors to this clusters. After upgrade, I started to have problems with HttpSession replication. Starting debugging JXTA, Shoal and the Web Container didn’t help at all. Until I found this page Memory Replication & Multi-threaded Concurrent Access to HttpSessions. My applications was doing multi-thread concurrent access some times (Ajax) and this was the root cause of all lost sessions. I modified sun-web.xml from my application, accordingly with the ...]]> http://www.randombugs.com/java/glassfish/glassfish-cluster-211-httpsessions-replication-multithread-concurrent-access.html/feed 0 http://www.randombugs.com/java/glassfish/upgrade-glassfish-21-211.html http://www.randombugs.com/java/glassfish/upgrade-glassfish-21-211.html#comments Tue, 29 Dec 2009 13:39:54 +0000 admin http://www.randombugs.com/?p=625
For some reasons the asupgrade tool from Sun Glassfish doesn’t work if you want to upgrade your Glassfish from 2.1 to 2.1.1. The upgrade method what I will present you in the next post, probably, is not recommended by SUN, but it will work in most cases (clustered or not). Just follow this steps: 1. Stop all domains, node agents, instances from all cluster (or only the domain if you have only 1 server) 2. Rename Glassfish folder to g2.1 3. Install glassfish 2.1.1 $ java -Xmx256m -jar glassfish-installer-v2.1.1-b31g-linux.jar $ cd glassfish $ chmod +x lib/ant/bin/ant $ ...]]> http://www.randombugs.com/java/glassfish/upgrade-glassfish-21-211.html/feed 0 http://www.randombugs.com/recovery/vmfs-datastore-missing-2.html http://www.randombugs.com/recovery/vmfs-datastore-missing-2.html#comments Thu, 22 Oct 2009 11:17:19 +0000 admin http://www.randombugs.com/?p=617
After successfully install of ESXi 3.5 server, my datastore1 disappeared unexpectedly after first or second reboot. Is possible to be because of my “hacks” in “Advanced Settings”, but I’m not very sure about that. Looking in /var/log/messages I spotted some very strange errors: Error Stream from partedUtil while getting partitions: Error: The partition table on /dev/disks/vmhba0:0:0:0 is inconsistent. There are many reasons why this might be the case. However, the most likely reason is that Linux detected the BIOS geometry for /dev/disks/vmhba0:0:0:0 incorrectly. GNU Parted suspects the ...]]> http://www.randombugs.com/recovery/vmfs-datastore-missing-2.html/feed 2 http://www.randombugs.com/java/glassfish/changing-logging-system-glassfish-21.html http://www.randombugs.com/java/glassfish/changing-logging-system-glassfish-21.html#comments Mon, 28 Sep 2009 18:04:20 +0000 admin http://www.randombugs.com/?p=606
A lot of people are not satisfied by the default Java Logging (JUL) in Glassfish. Also, myself I encountered some problems on clustered environments where we should have one single log and not one log for each instance. Trying to change the logging system in Glassfish it looks to be almost impossible , but I found a very interesting project java.util.logging to log4j Bridge and the sky become more clear for Glassfish logging. Jul to Log4J Bridge are part of log4J project and is very useful when you ...]]> http://www.randombugs.com/java/glassfish/changing-logging-system-glassfish-21.html/feed 0 http://www.randombugs.com/java/dbappender-log4j-12.html http://www.randombugs.com/java/dbappender-log4j-12.html#comments Thu, 24 Sep 2009 20:19:46 +0000 admin http://www.randombugs.com/?p=595
Initially, DBAppender for Log4j was introduced in version 1.3 of Log4j, but this version was ABANDONED by Apache team. DBAppender is very useful when we want to send our log on a JNDI resource and not on standard JDBC or file. If you need just logging in a database for your application, then you should use JDBCAppender. If you want to log on a JNDI or Database Connection Pool the DBAppender is for you. In this post I will show you how to get, compile and quick test the DBAppender. 1. ...]]> http://www.randombugs.com/java/dbappender-log4j-12.html/feed 5 http://www.randombugs.com/linux/tuning-linux-system-database.html http://www.randombugs.com/linux/tuning-linux-system-database.html#comments Thu, 16 Jul 2009 17:24:13 +0000 admin http://www.randombugs.com/?p=567
In my experiments with databases I was constrained to tune the system together with the databases. A system what will run a database is quite different from any other server system, because databases put a lot of stress on the IO and especially on the disks (probably the file servers too). Hardware is not all you should tune your system as much as possible. In this post I will talk about Linux with Ext3 (is what I have right now), but on future I will test OpenSolaris with ZFS. 1. ...]]> http://www.randombugs.com/linux/tuning-linux-system-database.html/feed 2 http://www.randombugs.com/linux/mysql-postgresql-benchmarks.html http://www.randombugs.com/linux/mysql-postgresql-benchmarks.html#comments Thu, 18 Jun 2009 14:25:25 +0000 admin http://www.randombugs.com/?p=458
We are living interesting times ... MySQL was first purchased by SUN and now SUN was purchased by ORACLE. I don't know what future will reserve for MySQL, but in this moment it seems MySQL is coming very very close to PostgreSQL. We are NOT talking about MySQL with MyISAM, we are talking about MySQL with InnoDB, because I'm directly interested in a set of properties what PostgreSQL already have them built-in and MySQL achieve them through InnoDB (and the new Maria Data plugin). This properties are Atomicity, Consistency, Isolation, Durability = ACID, in other words, very stable, good integrity and crash proof database. Why an ACID database? Sometimes we are more interested in ACID for our data than raw speed. For example do you keep your savings to a bank who is running a NON ACID database? I think you understand my concern. ]]> http://www.randombugs.com/linux/mysql-postgresql-benchmarks.html/feed 45 http://www.randombugs.com/linux/gpg-ubuntu-debian.html http://www.randombugs.com/linux/gpg-ubuntu-debian.html#comments Wed, 13 May 2009 12:40:28 +0000 admin http://www.randombugs.com/?p=443
Gpg is stands for Gnu Privacy Guard and is a free alternative to the PGP cryptographic software. GnuPG (or GPG) follows the RFC 4880 which is the standard specification of OpenPGP. The most important thing GPG is interoperable with PGP. GPG is build as a command line utility but also have several front-ends for KDE, Gnome and other Linux desktops, but also is directly integrated in other software like: Email Clients as Mozilla Thunderbird, Evolution, Kmail, Instant Messaging as PSI, Fire, Browsers as Mozilla Firefox etc. GnuPG encrypts messages using ...]]> http://www.randombugs.com/linux/gpg-ubuntu-debian.html/feed 2 http://www.randombugs.com/linux/encrypting-decrypting-files-ubuntu.html http://www.randombugs.com/linux/encrypting-decrypting-files-ubuntu.html#comments Tue, 05 May 2009 12:27:27 +0000 admin http://www.randombugs.com/?p=434
This days we shouldn’t trust in anything. The Internet is full of worms, trojans, viruses and they are spreading more and more. Even if you have a firewall is not enough. The best security for your computer is to have it unplugged from power and network … and even then you cannot be 100% about security of your stored data. So today we will talk about encryption under Linux. I will show you how to do it from console and from KDE Windows manager. We have several possibilities to encrypt ...]]> http://www.randombugs.com/linux/encrypting-decrypting-files-ubuntu.html/feed 0