Silent Data Corruption (SDC)

Silent Data Corruption (SDC)

Silent Data Corruption (SDC). Q: apa itu data corruption? Data corruption artinya data ketika dibaca tidak sama seperti ketika ditulis. Artinya data tersebut berubah. Q: cara mendeteksi data corruption? bisa pake checksum (md5, SHA). trus nanti akan keluar sebuah nilai. nilai yang keluar ini bisa dikatakan sebagai fingerprint dari data tersebut. contoh command: md5sum file_name (more…)...
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How to do mysql find replace

How to do mysql find replace

How to do mysql find replace. So today, we have a need to modify entries in our mysql database. We need to find a pattern (a word) on each record and replace with another pattern, so its like find and replace. unfortunately, this cannot be done with ordinary update command :-( as it will replace the whole content. (more…)...
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The effect of SSD on Virtual Machine performance

The effect of SSD on Virtual Machine performance

The effect of SSD on Virtual Machine performance. Well, today, we have something unusual compared to our previous SysAdmin classes. it is because we now use SSD in our hypervisor. During the training, the hypervisor is used to host virtual machines according to the scenarios. sometimes we need to install more than 10VMs at the same time which takes ages in the previous storage. In this test, we install solaris OS on proxmox hypervisor. For your information, Installing Solaris 10 on proxmox hypervisor, is a little bit tricky as you need to carefully select hardware for the Operating System. Wrong selection of hardware, can lead to incompatibility and result to kernel panic :-(. Therefore, some of the hardware doesnt support hardware-assisted virtualisation (intel-vt / AMD-V) which result to slower performance. we are also unable to use hardware with optimised driver like virtIO disk / network, simply because the OS doesnt support it. in our previous test, we installed a solaris 10 (update8)...
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Change default link type on wordpress

Change default link type on wordpress

If you are an active blogger or a staff that often updates contents of a website, most likely you will put image on your post. and if your platform is based on wordpress you will see that there is an option of how the image is link. This article will discuss a small tips to configure default link type on wordpress which could save your time by setup default selection of that option. (more…)...
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Troubleshooting inotify issue: Too many open files

Troubleshooting inotify issue: Too many open files

This time, we do troubleshooting inotify issue: too many open files. the story begun when there were many users having difficulties of accessing VM's console on proxmox hypervisor. when users clicked the console menu, it doesnt appeared as expected, only gives a blank pages with error message like the picture above. Some of can access smoothly, but others failed. By observing this behaviour, it seems like there an issue with resource limitation where when it reached the threshold level more users cannot be served properly. (more…)...
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What needs to be done after a cyber attack

What needs to be done after a cyber attack. In the previous article (here and here), we have discussed a way to identify that our system was attacked by somebody, either the attack was successful or not. next question is What needs to be done after a cyber attack / during the attack (if you know its currently happening where you are watching what they are doing through the log file). (more…)...
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How to identify a cyber attack

How to identify a cyber attack

If somebody is doing something that could harm you physically, then you will know immediately that the person is attacking you by seeing the movement that he/she is doing. So the processes are: receive input (incoming movement), analyse it (is it an attack or not), and decide the action. very simple :-). This article will discuss topic about How to identify a cyber attack. In the previous article, we have discussed several types of attack on cyber world. Now, the next question is, how to identify a cyber attack on my system / network? (more…)...
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What is DOS, DDOS, bruteforce (cyber attack)

What is DOS, DDOS, bruteforce (cyber attack)

What is DOS, DDOS, bruteforce. The word "attack" is not only belong to martial arts or military. In IT world we also use this term "attack" to describe an action that is done by a system to damage or destroy the target system / network. In this article we will discuss cyber attack, particularly about what is DOS, DDOS, bruteforce. and these attack usually related to each others. (more…)...
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Reseting wordpress admin password with adminer

Reseting wordpress admin password with adminer

Reseting wordpress admin password with adminer. So today i have been given a task to manage a wordpress-based website. unfortunately, the admin username and password is unkown. I have ftp access to the hosting server, and by reading the confing file, i know how to access the database (IP address, username, password). this article will be talking about reseting wordpress admin password with adminer. Why use adminer? because adminer is lightweight application. only one file, with less than 1MB size. compared to phpmyadmin, its a massive difference. (more…)...
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