How to get processes’ I/O utilization percentage

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Two notices: 1, a process has only one main thread which is itself. 2, a process has many threads. Solution 1: Please use taskstats [1] related interfaces, and send TASKSTATS_TYPE_PID and TASKSTATS_TYPE_TGID commands to kernel to get a process’s ‘blkio_delay_total’ parameter for a process with one main thread and a process with threads separately. Solution
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For QEMU/KVM, how to share data between host and guest

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General question for developers to access data between VM and VMM. As I know, paravirtualization solution is a good way to share data for VM and VMM since it has better performance. Please use Virtio 9p solution for QEMU/KVM. Note that you need to load 9p related modules for guest kernel. Add following in your
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Cannot make directory ‘/var/run/screen/S-apache’: Permission denied

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Hello! Im trying to create a screen folder for the user apache, Not root. But it seems to fail, I have no idea on how to fix this issue. I only get the error: Cannot make directory ‘/var/run/screen/S-apache’: Permission denied Im using Cent OS 7 There may be various possible reasons. 2 common reasons: screen
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How to add PHP DOMDocument extension to httpd in CentOS 7?

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Just migrated a PHP site to a new server. However, in /var/log/httpd/error_log, there are errors like [:error] [pid 2810] [client 61.92.242.24:43372] PHP Fatal error: Class ‘DOMDocument’ not found in /var/www/…/some.php on line 16 How to add PHP DOMDocument extension to httpd in CentOS 7? You need to install the package php-xml to have DOMCoument support
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Where is MySQL / MariaDB storage location by default on CentOS 7?

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Where is MySQL / MariaDB storage location by default on CentOS 7? No special configuration to the MariaDB from official repository of CentOS. On CentOS 7 Linux it is usually by default /var/lib/mysql But here I give you another “hacky” way to find it out. The method is to find out the mysql daemon mysqld’
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How to make iptables/ip6tables configurations permanent across reboot on CentOS 7 Linux?

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How to make iptables/ip6tables configurations permanent across reboot on CentOS 7 Linux? CentOS 7 uses FirewallD by default. If you would like to manage iptables/ip6tables rules directly without using FirewallD, you may use the old good iptables-services service which will load the iptables/ip6tables rules saved in /etc/sysconfig/iptables and /etc/sysconfig/ip6tables when it is started during boot
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How to convert a piece of HTML code to plain text in PHP?

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How to convert a piece of HTML code to plain text without leading and ending spaces in PHP? For example, I would like to convert <div> <b>hello</b> world</div> to a string hello world You may use this piece of code in PHP to strip HTML tags, remove leading and ending spaces and convert special characters
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How to upgrade vim to version 8 on CentOS 7?

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vim on CentOS 7 is version 7.4 with patches 1-160: $ vim –version VIM – Vi IMproved 7.4 (2013 Aug 10, compiled Dec 21 2016 17:00:20) Included patches: 1-160 How to upgrade it to version 8 which is the latest major version? Update on Oct 23 2018: the repository introduced in the original method is
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How to find out all files with replication factor 1 in HDFS?

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How to find out all files with replication factor 1 in HDFS? The hdfs dfsadmin -report shows there are blocks with replication factor 1: Missing blocks (with replication factor 1): 7 How to find them out? You can run hdfs fsck to list all files with their replication counts and grep those with replication factor
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How to change the maximum uploading size for PHP with Apache on Linux?

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How to change the maximum uploading size for PHP with Apache on Linux? PHP has parameters to control the maximum uploading size. Here, we use Ubuntu 18.04 LTS default version as an example. First, open the php.ini configuration file using your favorite editor /etc/php/7.2/apache2/php.ini Then, find the following parts ; Maximum size of POST data
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How to add a prefix string at the beginning of each line in Bash shell script on Linux?

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How to add a prefix string at the beginning of each line in Bash shell script on Linux? For example, assume we have a file a.txt: line 1 line 2 I want to have, pre line 1 pre line 2 You may use sed, the stream editor for filtering and transforming text: sed -e ‘s/^/pre
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How to detect whether a file is being written by any other process in Linux?

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How to detect whether a file is being written by any other process in Linux? Before a program open a file to processes it, it wants to ensure no other processes are writing to it. Here, we are sure after the files are written and closed, they will not be written any more. Hence, one-time
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How to make CentOS Linux to load a module automatically at boot time?

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How to make CentOS Linux to load a module, say ixgbe, automatically at boot time? I am using CentOS 7. You can create a text file <some name>.conf in the /etc/modules-load.d/ and list the modules to be loaded there, one per line. The systemd-modules-load.service daemon will read these files and load the modules. Check more
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How to get the highest temperature from all sensors in a server on Linux?

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It is useful to monitor a server node’s temporary. Among all the sensors’ temperatures, the higher one may be a very important one. How to get the highest temperature from all sensors in a server on Linux? You can use this command to get the the highest temperature from all sensors in a server on
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