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A person who is fearful or contemptuous of that which is foreign, especially of strangers or of people from different countries or cultures. but these xenophobia is elevating rapidly in the western countries it is having numerous causes as well as to kick off, Like all phobias, there is no universally specific cause that leads to the development of xenophobia but some symptoms show that if it left untreated it can have some dangerous effects like Distrust aimed specifically towards cultures perceived by the phobic to be different.

Rash generalizations and stereotypes aimed at a set of people who can be identified by superficial qualities and Finding abusive and prejudiced behavior humorous.

On the other hand, some possible solutions can be proved helpful to combat this problem firstly mental health therapy can be fruitful for the person’s irrational and extreme fear. The patient and therapist talk about why the fear unfounded, how they can come to terms with any traumatic experiences that caused the phobia, next awareness given to the person who is having this problem can lead to a peaceful state of mind of that person.

In summary, every problem has possible solutions but this cannot be worked without the help of self-motivation that needed to be given to victim himself.



In today’s world, where just about everything is more convenient and accessible due to advances in technology across almost all sectors, it may seem as though it’s a misnomer to even mention any disadvantages of technological advances. However, technologyhas proved boon and bane for the society. Lets us delve deeper on this issue in forthcoming paragraphs.

To commence with, Technology advances show people a more efficient way to do things, and these processes get results. For example, education has been greatly advanced by the technological advances of computers. Students are able to learn on a global scale without ever leaving their classrooms. Moreover, medical discoveries occur at a much more rapid rate. Result of advancement in technology means cost savings for business owners. It helps to allow them to invest in growth in other areas of the business, which contributes on a positive level to the economy as a whole.

On the contrary, it has disadvantages too. The more advanced society becomes technologically, the more people begin to depend on computers and other forms of technology for everyday existence. This means that when a machine breaks or a computer crashes, humans become almost disabled until the problem is resolved. This kind of dependency on technology puts people at a distinct disadvantage, because they become less self-reliant. Its continuously making the masses fatigue and lazy.

To sum up all, as machines and computers become even more advanced and efficient, this will continue to be a growing disadvantage of technology and an issue that has a global impact will also increase but people should make a balance in using the technology and man power resources for the betterment of humankind.

Essay-Do you think that consumer should avoid over packed products or it is the responsibility of the producer to avoid extra packaging of products?” Give your views or any relevant example with your own experience.

Essay-Do you think that consumer should avoid over packed products or it is the responsibility of the producer to avoid extra packaging of products?” Give your views or any relevant example with your own experience.


In my opinion, the customer should discard the product with extra packaging as well as the manufacturer also share an equal responsibility of the commodities. On one hand, consumers should not buy the over packaged products, simultaneously they should buy products which have biodegradable packaging and finally shouldof segregate the dangerous packaging material while disposing off. On the other hand, the manufacturers should always look out new technology for packaging which is eco-friendly, go for bare minimum packaging that is required and should always follow the environmental laws.

Firstly, a lot of damage is done to the environment when packaging material is not properly disposed off. For example, plastic and polyethylene are not biodegradable and remains intact even after 1000 years. Secondly, lots of cardboards are used as packaging material for which lots of trees are cut down, which is the major cause of deforestation. Moreover, with additional packaging, the cost of the product also increases. Over packaging is also hazardous for the animal and aquatic life, as many animals’ diesby consuming polyethene and marine life is disturbed and choked when these materials are disposed in rivers or sea.

As a responsibility, the consumers should discard the over-packaged products and should go for biodegradable packaging products. Secondly, they should not dump the packaging materials along with the garbage. Any packaging material if there should be properly disposed off or recycled. Most importantly all the consumers should follow the environmental rules and regulation which will make their surrounding eco-friendly. Lastly, knowledge about keeping the environment clean and safe should be given in schools and colleges and citizens should organize awareness campaigns with the help of NGOs about the ill effect of extra packaging.

Lastly, the manufacturer should also take equal responsibility to avoid extra packaging. They should always look out for some new technology for biodegradable packaging. Secondly, producers should pack the products with only bare essential packaging. Finally, producers should always follow the environment rules and regulations in terms of extracting packaging material

All in all, it can be concluded that both consumers and manufacturers should share the responsibility and go hand in hand to avoid the ill effects of extra packaging.

Essay – Some people believe laws change human behaviour. Do you agree with it?

Some people believe laws change human behaviour. Do you agree with it?

Few people are of the view that the rule of the land changes the conduct and the nature of persons. I, totally agree with this statement because the presence of law builds up the confidence among the citizens and make the society disciplined. Furthermore law abiding citizens live a safe life with harmony among themselves.

Firstly, with the presence of certain laws, the confidence among the civilians increases because every citizen feels that justice and fairness will be delivered to them. Law does not differentiate the citizens on the basis of money, sex or creed. That is why the law instils confidence among the citizens. Recently in 2012, changes have made in the Indian laws, and now the laws to protect the women are even more stringent and strict. This act has grown the confidence of the women more.

Secondly, with the presence of law people feel safe. For instance in many countries, it is mandatory to wear helmet and fasten the seat belt while driving the vehicles. Obeying the traffic laws make the people safe and it brings discipline among them.

Thirdly, certain laws also help the citizens to remain healthy. For example narcotics laws prevents the people from the drug abuse. Harsher punishments are awarded to the offenders in many countries. Healthy and fit people tend to be more efficient and happy.

Finally, it can be concluded that law do affect the behaviour of the people. A common man lives his life stress free, while the criminals are always in a fear of being caught.

pvresize command


pvresize is a tool to resize Physical Volume which may already be in a volume group and have active logical volumes allocated on it.

Expand the PV on /dev/sda1 after enlarging the partition with fdisk:

pvresize /dev/sda1

Shrink the PV on /dev/sda1 prior to shrinking the partition with fdisk (ensure that the PV size is appropriate for your intended new partition size):

pvresize --setphysicalvolumesize 40G /dev/sda1

SSH vulnerabilities: HMAC algorithms and CBC ciphers

e defaults in the various RHEL version differ and the current default can be found in manual page for sshd_config. For example RHEL6:

The default is:

You can remove the CBC ciphers by adding the line for RHEL7:

Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,,,,arcfour

The line for RHEL6:

Ciphers aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,arcfour

The line for RHEL5 (note the order of ciphers – the RC4 cipher is also known for several vulnerabilities and should not be used):

Ciphers aes128-ctr,aes192-ctr,aes256-ctr',arcfour128,arcfour256,arcfour
  • Restart sshd to apply the changes:
# service sshd restart


  • In order to remove HMAC MD5, add or modify the “MACs” line in /etc/ssh/sshd_config as below.

The defaults in the various RHEL version differ and the current default can be found in manual page for sshd_config. For example RHEL6:

The default is:

You can remove the hmac-md5 MACs by adding a line to /etc/ssh/sshd_config for RHEL7:


The line for the RHEL6:

MACs hmac-sha1,,hmac-ripemd160,hmac-sha2-256,hmac-sha2-512,

The line for RHEL5:

MACs hmac-sha1,hmac-ripemd160
  • Restart sshd to apply the changes:
# service sshd restart

Changing temporary directory for sort – bash

I was sorting a very big file using Linux sort command and unfortunately the sort failed as there was not enough space on my /tmp directory.

$ sort -t “|” -k5 ka.log.32323112.out > ka.log.32323112.out
sort: /tmp/sort1928700448: write error: No space left on device

just to mention, sort by default uses /tmp for temporaries.

So, how you can tell sort to use some other directory for temporaries ?

From man pages of sort(1)

-T, –temporary-directory=DIR
use DIR for temporaries, not $TMPDIR or /tmp; multiple options specify multiple directories

$ sort -T /home/jadu/ -t “|” -k5 ka.log.32323112.out > ka.log.32323112.out

It worked 🙂

Another way would be : export env variable TMPDIR to some directory which have sufficient space.


$ export TMPDIR=/path/to/other/directory
$ sort -t “|” -k5 ka.log.32323112.out > ka.log.32323112.out

It worked too 🙂

MySQL InnoDB engine B + tree index simple finishing instructions

There are several types of InnoDB engine tables in MySQL (the following index, no special instructions, refers to the InnoDB engine table index.)
0 = Secondary Index, 2-level index,
1 = Clustered Index, clustered index
2 = Unique Index, Unique Index
3 = Primary Index, Primary Key Index
32 = Full-text Index, Full Index
64 = Spatial Index
128 = A secondary index that includes a virtual generated column.

The second-level index, the clustered index, the unique index, the primary key index, the second-level computed column index, and the logical storage structure, are all stored in the B + tree to store
this point with the B + tree index logical storage structure of the other database Not too different, the above several indexes are divided from the logical point of view.

If the physical storage from the point of view, MySQL in these types of index can be divided into clustered index and secondary index (or non-clustered index)
Among them, the primary key index and clustered index, can be classified as clustered index, Unique index, secondary computed column index data nonclustered index.

The clustered index in MySQL

MySQL clustered index is based on the primary key, the entire table of data, logically organized into a B + tree, so a table can only be a clustered index.
The non-leaf node stores the clustered index key value, and the leaf node stores the data itself in the table, and the leaf node and the leaf node are connected together by a two-way list.

Know the MySQL clustering index before the first look at the MySQL primary key generation mechanism.
MySQL InnoDB must have a primary key,
if the time specified in the construction of the primary key, then the primary key is the main key of the table (sounds so awkward, mainly with the primary key is not specified, the automatic generation of the main key for comparison)
If the primary key is not specified, the storage engine will automatically create a primary key column for the table.
1) For the table that specifies the primary key, the primary key is the primary key index.
2) For tables that do not specify a primary key, If there is a unique index (one or more) that is not empty, the (first) non-null unique constraint is the primary key.
3) For a table that does not specify a primary key and there is no unique constraint, a primary key is generated by default. The index is “clustered index”, in
fact, the former “primary key index” and the latter “clustered index”, the physical storage can be attributed to clustered index

1, explicit primary key index (clustered index)

In the following screenshot, the test_index_type_1 is created
when the primary key is specified in the table, the primary key defaults to the primary key index. The index type is 3 (from the physical storage point of view, the index is
created ) Level index, the index type is 0 (from the physical storage point of view, is non-clustered index)



2, non-empty unique constraints generated by the primary key index (clustered index)

The following screenshot, created test_index_type_2,
did not specify the primary key when the table was created , but specified a unique non-null constraint, then the field would be used as the primary key, and the resulting index type would be 3 (from the physical storage point of view index)




3, the system default primary key generated clustered index (clustered index)

In the following screenshot, the test_index_type_3 table was created,
the primary key was not specified at the time of the table, and the unique non-null constraint was specified. The InnoDB engine automatically generates a 6-byte pointer. The generated index type is a clustered index, (From the physical storage point of view, is the clustered index)



Nonclustered index

The non-clustered index, the nonclustered index is also the structure of the B + tree to store the data.
The difference from the clustered index is that the leaf node of the nonclustered cable stores only the key value of the index + the key value of the clustered index, but does not include All non-index key values.

1, unique index generated by the unique index (non-clustered index)

The following screenshot, created the test_index_type_4 table,
specify the id as unique, then the id will automatically create a unique index.





2, the manual creation of a unique index (non-clustered index) The
following screenshot, created test_index_type5 table,
manually create a unique index, then the index type is unique index



3, manually created secondary index (non-clustered index) The
following screenshot, created test_index_type6 table,
that manually create an index (not specified unique), then the index type for the secondary index


4, the calculation of the column index, in the calculation of the column manually create the index (non-clustered index) The
following screenshot, created test_index_type7 table,

test_index_type7 there is a calculation column, after the completion of the calculation column in the calculation of the index,


to sum up:

Overall, MySQL several types of B + tree index is still relatively easy to understand, with the SQL Server index is also similar.
MySQL’s InnoDB engine table, the primary key index, non-null unique constraint generated by the clustered index, clustered index, from the physical storage point of view are data clustered index.
Primary key index, non-empty unique constraint generated clustered index, clustered index, the three have a distinct feature, all require that the column is non-empty and unique.
The other is that MySQL can not explicitly create a clustered index, that is, create clustered index.

This is very different from SQL Server,
1, in SQL Server, if you do not specify the primary key, or specify the primary key is not specified but nonclustered, then the table is for the heap table, the system will not add the default field as a clustered index
2 , SQL Server primary key can only be the primary key, you can not clustered index (by default the primary key is clustered index).

The clustered index can be specified on any column, either a non-primary key column, a non-unique, nullable, repeatable column, such as


Nginx server 10000 concurrent optimization test (ab test tool)

1.nginx monitoring module

1) Compile nginx with the parameter –with-http_stub_status_module

#/usr/local/nginx/sbin/nginx -V
./configure --user=www --group=www --prefix=/usr/local/nginx --with-http_stub_status_module --with-http_ssl_mo

./configure --prefix=/usr/local

2) Modify the nginx configuration file and add the monitoring status configuration

Add the following code to the server block of nginx.conf

location /nginx_status {
    # Turn on nginx stats
    stub_status on;
    # I do not need logs for stats
    access_log   off;
    # Security: Only allow access from IP #
    # Send rest of the world to /dev/null #
    #deny all;
   Active connections: The number of active connections initiated by the backend. 
  Server accepted handling requests: Nginx handled a total of 655 connections, successfully created 655 times handshake (proved no failure in the middle), handled a total of 1985 requests. 
  Reading: Nginx Number of Header messages read to the client. 
  Writing: Nginx Number of Header messages returned to the client. 
  Waiting: In the case of keep-alive, this value is equal to active - (reading + writing), meaning that Nginx 
/usr/local/nginx/sbin/nginx -t  
/usr/local/nginx/sbin/nginx -s reload
 2. Set the maximum number of connections (50000) / tcp speed up the recovery of the number of conn

echo 50000 > /proc/sys/net/core/somaxconn

echo 1 > /proc/sys/net/ipv4/tcp_tw/recycle
echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse
echo 0 > /proc/sys/net/ipv4/tcp_syncookies


3. set to open more files

ulimit -n 50000

vim /etc/nginx/nginx.conf
worker_rlimit_nofile 10000;

worker_connections 10240;

/usr/sbin/nginx -t
/usr/sbin/nginx -s reload



4.ab -c 5000 -n 100000 

erver Software: nginx/1.4.6
Server Hostname:
Server Port: 80

Document Path: /index.html
Document Length: 65 bytes

Concurrency Level: 5000
Time taken for tests: 46.416 seconds
Complete requests: 100000
Failed requests: 90202
(Connect: 0, Receive: 0, Length: 90202, Exceptions: 0)
Write errors: 0
Non-2xx responses: 90282
Total transferred: 36624606 bytes
HTML transferred: 18815922 bytes
Requests per second: 2154.42 [#/sec] (mean)
Time per request: 2320.813 [ms] (mean)
Time per request: 0.464 [ms] (mean, across all concurrent requests)
Transfer rate: 770.55 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 18 1251 2273.8 824 31950
Processing: 298 839 299.1 855 6307
Waiting: 1 648 298.8 651 6194
Total: 408 2090 2323.2 1697 36083

Percentage of the requests served within a certain time (ms)
50% 1697
66% 1758
75% 1802
80% 1843
90% 2583
95% 4601
98% 8399
99% 8807
100% 36083 (longest request)


Linux server found strange port handling methods

Generally in the beginning of the need for their own company’s IT environment to have a general understanding of 1-2 months after the need to open the port has a clear understanding of what the port is used to do, whether it is illegal open port , Their own mind to be the number of unknown Trojans through a strange port to the black out on the embarrassment. So as the operation and maintenance personnel need to open the port of each company has a clear understanding of the port, at the same time have to face the strange port how to determine the port corresponding to what kind of service, the service is illegal and so on.

Need to use the command :

Ss -tnl       shows all tcp has been listening on the port

 Lsof -i : The port   displays all the processes that open the port


Working example:

One day through ss -tnl found that do not know the port is being monitored


For the port 49994 I do not know why it is doing, so use the lsof-i command to see which ports are open

It is found here that the port corresponds to the rpc.statd command.

(If prompted not to remember the command yum install-y lsof)

If you do not know rpc.statd, a very simple way is baidu

Through the baidu can know that the order is nfslock service of a process, if you want to close the port only need to close nfslock service

Service nfslock stop

And then perform ss-tnl found 49994 port disappeared

In the future if you encounter an unknown port can use the above method to judge.