Server and PC
Ethernet is also on the server is essentially a computer, compared to a home computer in terms of differences are as follows: 1. The server more stable
2. The home machine performance than is generally higher
Operation and maintenance engineers of the core responsibilities
Ensure uninterrupted operation of server
Enhance access efficiency
Ensure data security
To accomplish the above task, we must understand the core components of the server
Composition server
Server is the computer so little concern about the same but there are differences
power supply:
To uninterrupted operation of the server, it must ensure not cut
How to ensure uninterrupted power it, there is a common way
A dual power lines automatically switched to another line during power outage
UPS is essentially a large battery may provide power for more than 10 minutes, the purpose is to save the data before shutdown
Or owned generators
CPU
Central processor in the server space, CPU cores tend very much
Single Dual is a common call, the road is equal to the number of CPU
For example it is two dual quad-core CPU cores per CPU 4
RAM
The memory is a temporary memory, the advantage of speed, the disadvantage is the loss of a breakpoint, and the high cost
This means that we can not store data directly into memory
How do we improve the efficiency of the server do?
For medium and large enterprises:
Under concurrent read and write are very large, directly into the database, efficiency certainly can not keep up, so it should first data stored in the cache memory, or memory data of the order after reaching a certain idle time server persisted to the database,
But it has also brought new problems, if the server suddenly loses power, unsaved data will be lost, so the power supply is also put forward higher requirements!
SME:
Typically less read write, write data directly to the database, retrieve data from the database and then to the cache memory, the client obtains the data directly from memory
Buffer and cache:
We often refer to the cache in raising the efficiency of IO buffer two concepts
It refers to a buffer storage of data when data is written from outside the memory region is called a buffer memory
Refers to the cache memory when reading data from, the data storage area called a cache memory,
hard disk
Also known as the hard disk, it is a storage device using a magnetic material made of the advantage that can be permanently stored, and the low cost, the disadvantage is slow read and write
The main concern is the server hard disk interface type
Currently common SAS (commercial) STAT (civilian) PCIE (M2) solid expensive
Server common SAS interface, a size of 3.5 or 2.5
Hard drive size:
B KB MB GB TB PB (common) ZB
Hard drive is the ultimate location data stored, so the higher security requirements, if only a single disk, then, performance and security can be guaranteed
So the server configuration usually raid
works
refers to a disk radi aligned, consciousness is integrated into the plurality of physical disk groups together form a disk,
radi according to different performance and safety requirements, configure different arrays
Several common
raid0
More than two disks, data is divided sequentially stored on different disks, greatly improving the capacity of the disk, but does not provide any fault tolerance,
Features: large capacity unsafe speed without loss, the fastest
RAID1
Two or more disks, typically an even number, between the two storage disk mirroring, i.e. a full backup, the program will lose 50% of the storage capacity, but provides high security, as long as the timely replacement of the hard disk can be damaged ensure data security, there is no impact on the performance of a larger capacity loss
raid3
Separate parity disk storage, so that when a disk is destroyed to restore lost data by parity, 1/3 loss of capacity
High efficiency but low continuous data read and write random access efficiency
raid5
Distributed Parity
Parity data is distributed on each piece of disk, more stable, the most damaging piece of the more common high performance storage
Remote Management Card
Servers have integrated management card, the drawback is you can not view can only execute commands directly to a specific implementation process
You can also install a separate management card, the advantage of the process is the same view specific machine before the first stand
##
Cabinets
Cable wiring inside the cabinet must be arranged neatly tag http://www.sohu.com/a/13503281_103475
The origin of Linux
In 1969 the US General Electric jointly developed at Bell Labs supports multi-operating system that is used in UNIX, formerly known as MULTICS, know that 1970 can only support two users, when the author jokingly refer to "UNiplexed Information and Computing Service", abbreviated as "UNICS "later, whichever is homophonic ie UNIX
1984 Andrew S. Tanenbaum unix-based applied to the development of teaching minix
After the enactment of the trial in the unix standard industry fears it will be charged, and from Richard Matthew Stallman initiated and formed, FSF Free Software Foundation,
And launched the GNU project, originally planned to develop a completely free operating system, but the Hurd kernel has not been completed, but is not nothing to develop a very good shell interpreter bash, has launched a follow-up to the GPL
GNU GPL clause is to ensure that the software is free to use, copy, modify and distribute, all GNU software has added a prohibition others without any limitation of the rights granted to all provisions of anyone agreement. a) you have the freedom to run the program for any purpose. b) you have the freedom to modify the program to meet their needs. c) You have the right to republish the secondary part, either give away you may also charge a fee. Hat Red d) You have the right to publish modified versions of the program, so that other people benefit from your improvements.
April 13, 1991 Linus Torvalds released on comp.os.minix say that they have successfully transplanted to bash on minix
1991 October 5 in comp.os.minix newsgroup post messages on the outside officially announced the birth of Linux kernel
linux application areas:
it server
Embedded Development
Desktop PC
Release:
Redhat
Is Red Hat's Linux distribution, for the commercial market, including mainframes. Red Hat began offering 10 years of support for each version of Enterprise Linux from Red Hat Enterprise Linux 5. The Red Hat Enterprise Linux often referred to as RHEL.
Is a commercial version, is not available for free download and use. Need to buy Red Hat's business services can legally obtain and get commercial support
CentOS
Advantage : very stable and reliable; free to download and use; free security updates for more than seven years; drawback : the lack of the latest Linux technology; sometimes the project failed to fulfill its commitment to provide timely security updates and new stable version
Ubnhu
Advantages : Fixed release cycle and support period; with a 5-year long-term support (LTS) variants security updates; novice-friendly; wealth of documentation , both official and user selfless contribution disadvantages : Debian and has some compatibility issues; major update frequently possible loss of some users, Unity user interface has been criticized as more suitable for mobile devices, instead of the computer;
Debian
Advantage : very stable; remarkable quality control; includes over 30,000 software packages; supports more than any other Linux distribution processor architecture drawback : Conservative - With support for many processor architectures, does not always contain technical updates ; slow release cycle (every 1 - stable released once 3 years)
Fedora
Advantages : highly innovative; outstanding safety features; a lot of support packages; strict adherence to the concept of free software; Live CD with many popular desktop environments availability drawback : Fedora's priorities tend to tend to business functions, rather than the desktop availability ; some good edge features, such as early switching to KDE 4 and GNOME 3, occasionally some of the desktop user alienate
Install linux operating system
Download the latest version: https://www.centos.org/download/
Download Version History: http://vault.centos.org
Installing VMware
Create a virtual machine
Install centos
NIC naming convention
Partitioning Setup
Network Configuration
Brother virtual machine provides three network options
1. bridge mode can connect to the Internet, but require exclusive IP network of a host
2.NAT network address translation, will create a virtual network card, and set up a subnet, will not take up the host's IP network segment (the same network segment can have up to 253 network address is 0, 1 usually Gateway 255 can not be used)
3. Only hosts, virtual machines and host communications can not only connect to the Internet
The installation is complete
log in system
SSH service confirmation:
ss -lntp
xshell optimization
Production clone
1. Locate the network card configuration file is deleted UUID avoid conflicts
2. Clone Virtual Machine
3. Modify the IP address cloning machine to avoid conflicts
##