TCP dump and NMAP

1, to detect whether the specified network segment FTP service host, do not do DNS reverse analysis

nmap -sS –n –p 21 2, to detect whether the specified server has a specific port services

nmap –n –p T:21-25,80,110,3389–sS

3, the use of TCP connection scan to detect the specified server, even if it […]



EMC has released ScaleIO 2.0 couple of days ago. More information –

Some new features (source ScaleIO 2.0 release notes):

Extended MDM cluster – introduces the option of a 5-node MDM cluster, which is able to withstand two points of failure. Read Flash Cache (RFcache) – use PCI flash cards and/or SSDs for caching of the […]

Useful commands for Hadoop HDFS troubleshooting

[hadoop@master ~]$ hdfs dfsadmin -report 17/04/13 00:06:51 WARN util.NativeCodeLoader: Unable to load native-hadoop library for your platform… using builtin-java classes where applicable Configured Capacity: 37576769536 (35.00 GB) Present Capacity: 33829806080 (31.51 GB) DFS Remaining: 33829789696 (31.51 GB) DFS Used: 16384 (16 KB) DFS Used%: 0.00% Under replicated blocks: 0 Blocks with corrupt replicas: 0 Missing […]

CentOS 7.3 under the Hadoop 2.7.2 cluster

CentOS 7.3 under the Hadoop 2.7.2 cluster

how to setup a Hadoop cluster on CentOS linux system. Before you read this article, I assume you already have all basic conceptions about Hadoop and Linux operating system.

mv ifcfg-eno16777736 ifcfg-eth0 vi /etc/udev/rules.d/90-eno-fix.rules # This file was automatically generated on systemd update SUBSYSTEM==”net”, ACTION==”add”, DRIVERS==”?*”, ATTR{address}==”00:0c:29:9e:8f:95″, NAME=”eno16777736″


YumDownloader on CentOS 7 / RHEL 7


yum install yum-utils yumdownloader bind-utils [root@lab4 ~]# yum install yum-utils Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: * extras: * updates: Resolving Dependencies –> Running transaction check —> Package yum-utils.noarch 0:1.1.31-40.el7 will be installed –> Processing Dependency: python-kitchen for package: yum-utils-1.1.31-40.el7.noarch –> Processing Dependency: libxml2-python for package: […]



Red Hat Enterprise Linux 7 introduced a new scheme for naming network devices called “Consistent Device Naming”. It’s called Consistent Device Naming because previously the name of the devices [eth0,eth1,eth2] was completely dependant upon the order the kernel detected them as it booted. In certain circumstances, such as adding new devices to an […]

Nginx for serving files bigger than 1GB

ealize that nginx was not serving files larger than 1GB. After investigation I found that it was due to the proxy_max_temp_file_size variable, that is configured by default to serve up to 1024 MB max.

This variable indicates the max size of a temporary file when the data served is bigger than the proxy buffer. If […]

find large files on Linux

Find large files on Fedora / CentOS / RHEL

Search for big files (50MB or more) on your current directory:

find ./ -type f -size +50000k -exec ls -lh {} ; | awk ‘{ print $9 “: ” $5 }’


[]pwd /home []find . -type f -size +50000k -exec ls -lh {} ; | […]

Creating a partition size larger than 2TB on Linux

I had to mount and use a 3TB SATA HD on Linux, and as I thought, I wasn’t going to be able to format and create a new partition using fdisk command.

fdisk tool won’t create partitions larger than 2 TB. This is fine for desktop users, but on a production server you may need […]

HylaFAX with AvantFAX in CentOS 7

hylafax with avantfax installation on CentOS 7  .

With out any talk , lets start…..

Install needed packages ,

# yum install epel-release -y

# yum update -y

# yum groupinstall “development tools” -y

# yum install hylafax wget -y

Download AvantFax from there web site . AvantFax is using for Fax web GUI .


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