29. 01. 2019.

Putty for Linux copy/paste issue and solution

Putty is probably the most common tool to access Unix/Linux environments on Windows platform by using ssh protocol. Recently I’ve been in situation where I’ve got only Putty generated ppk file to access Unix server. Although I’ve asked if I can get open ssh generated file, that was not possible, as it was assumed that […]

28. 01. 2019.

Easy way to create Virtualbox VM’s internal network

Virtualbox is a very popular hypervisor which allows you to run guest virtual machines like Windows, Linux, BSD, Solaris etc. For various purposes you might want to combine several virtual machines into one network. In this post I’ll describe the easiest way of how to do that, which is good enough for most of the […]

24. 01. 2019.

Installing SQL Developer on Ubuntu

Today it is not necessary to introduce SQL Developer, Oracle’s main tool to work with databases. I’ve started to use SQL Developer from the beginning (2015, project Raptor, later renamed into SQL Developer). Before that, the only Oracle tool for working with it’s flagship database was SQL*Plus (and iSQL*Plus later). For that reason, most of […]

23. 01. 2019.

Python & Oracle Instant Client connection setup on Linux – part 2

In the previous article I’ve described how to install Oracle Instant Client and setup cx_Oracle Python driver correctly. You only need Basic package to install: Version 18.3.0.0.0 Base – one of these packages is required Basic Package – All files required to run OCI, OCCI, and JDBC-OCI applications Download instantclient-basic-linux.x64-18.3.0.0.0dbru.zip (72,794,506 bytes) (cksum – 3435694482) […]

04. 01. 2019.

Multipath I/O and Network bonding

Event though Multipath I/O and NIC bonding is more related to sysadmin and storage admin tasks, it is good idea to grab some knowledge about those keywords as they play important role in achieving good performance. In the series of articles about disk speed I explained why it is good to know what values you […]

21. 12. 2018.

How to quickly check disk(s) speed limit on Linux – part 3

This is the third part of a series of articles about measuring performance of disk subsystem. In the first part you can find details of how to measure disk performance by using dd command: https://www.josip-pojatina.com/en/how-to-quickly-check-disks-speed-limits-on-linux/ while in the second part you can find similar information by using the hdparm utility: https://www.josip-pojatina.com/en/how-to-quickly-check-disks-speed-limit-on-linux-part-2/ In this blog I’ll […]

14. 12. 2018.

How to quickly check disk(s) speed limit on Linux – part 2

In the previous part of disk speed series you can see one way to test disk speed by using special options of the dd command. In this article another utility – hdparm will be described. What is common with the previous way of testing HDD disk performance is in it’s simplicity, meaning you only need […]

04. 12. 2018.

How to quickly check disk(s) speed limit on Linux

Many times I can testify that IT professionals are talking about performance without even try the most simplistic tests to find out what are the HW capabilities/limits they have. One of the first things I usually do when facing with unknown environment is to run several tests to find out how much I can get […]

13. 09. 2018.

Bash performance tuning by example – How to delete 1 million files from file system, and how to do that fast?

In this article I’ll show my approach to solve real world performance problem by using bash scripting language.   Problem statement is: How to delete 1 million files from file system, and how to do that fast?   File system maintenance is important aspect of sysadmin job. It’s not only important to maintain file system, […]

16. 08. 2018.

Exadata / Linux crash – capturing kernel dump on Linux systems

This article has been motivated from real life issue experienced on Exadata system running a few dozen of Oracle databases. I have already written about Exadata shortcoming in one of previous articles where I stressed that one of the main disadvantages of Exadata machine is non-existent virtualization technology. Oracle recognizes Oracle VM as the only […]