FlamingBytes

From man page of iostat in Linux, %util is explained as below.

%util:

Percentage of elapsed time during which I/O requests were issued to the device (bandwidth utilization for the device). Device saturation occurs when this value is close to 100%.

I have seen many cases people misuse this metric when to tell if the system runs into disk I/O bottleneck.

iomerges parameter

In Linux, the file nomerges under /sys/block/xxx/queue/ enables the user to disable the lookup logic involved with I/O merging requests in the block layer.

One method to connect to the AKS cluster nodes is to create an interactive shell, aka debug pod.

This is a list of top classic coding questions which help understand various data structure and algorithms.

Adventure comes in many forms. Some you expect, some you don’t. Some have you excited, some make you dread. But if there’s one thing all my adventures have in common, it’s that they all somehow end up with my life being in danger.

“Kai, hurry! We’re going to be late to the festival!” Kate called.

Two pointers is typically used for searching pairs in a sorted array satisfying some condition in linear time.

1
2

sysbench /root/trg/sysbench/src/lua/oltp_delete.lua --mysql-user=root --mysql-password=0000abc! --mysql-socket=/ssddata/dmain/mysqld.sock --threads=32 --report-interval=10 --rand-type=uniform --time=60 --table_size=1000000 --tables=10 prepare
sysbench /root/trg/sysbench/src/lua/oltp_delete.lua --mysql-user=root --mysql-password=0000abc! --mysql-socket=/ssddata/dmain/mysqld.sock --threads=32 --report-interval=10 --rand-type=uniform --time=60 --table_size=1000000 --tables=10 run

Reference

• https://github.com/akopytov/sysbench/tree/master
• https://github.com/akopytov/sysbench/blob/master/src/lua/oltp_common.lua
• https://github.com/akopytov/sysbench/blob/master/src/lua/oltp_delete.lua

Intro

Postmark is a benchmark designed to simulate the behavior of mail servers. Postmark consists of three phases. In the first phase a pool of files are created. In the next phase four types of transactions are executed: files are created, deleted, read, and appended to. In the last phase, all files in the pool are deleted.

Intro

The Phoronix Test Suite is the most comprehensive testing and benchmarking platform available for Linux, Solaris, macOS, Windows, and BSD operating systems. The Phoronix Test Suite allows for carrying out tests in a fully automated manner from test installation to execution and reporting. All tests are meant to be easily reproducible, easy-to-use, and support fully automated execution. The Phoronix Test Suite is open-source under the GNU GPLv3 license and is developed by Phoronix Media in cooperation with partners.