The document appears to be a series of tweets from @tweetingsherry discussing various IT-related topics including servers, debugging tools like strace, MySQL optimization, and Git best practices. Specific points discussed include cattle vs pets architecture, using swap space, MySQL configuration like max connections and slow query logging, adding indexes, and using Git reflog and interactive adding/committing.

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@tweetingsherry
PETS AND PANDAS
😸🐶🐰 🐼 🐼 🐼

2. .
@tweetingsherry
Chris Sherry
Senior Software Engineer @passengerteam
@passengerteam

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@tweetingsherry
Chris Sherry
Senior Software Engineer @passengerteam
@passengerteam

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@tweetingsherry
discoverpassenger.com
@passengerteam

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@tweetingsherry
SERVERS

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@tweetingsherry
Cattle
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
Cattle
🔟 Assigned Numbers
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
Cattle
🔟 Assigned Numbers
♊ Are usually identical
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

9. .
@tweetingsherry
Cattle
🔟 Assigned Numbers
♊ Are usually identical
💰 You need more, you buy
more
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

10. .
@tweetingsherry
Cattle
🔟 Assigned Numbers
♊ Are usually identical
💰 You need more, you buy
more
🔫 Replaced when not in
good health
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
PETS
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
📛 Have names
PETS
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
📛 Have names
✨ Unique, special
PETS
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
📛 Have names
✨ Unique, special
⏳ Change over time
PETS
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
📛 Have names
✨ Unique, special
⏳ Change over time
🚑 Require bespoke care
PETS
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

16. .
@tweetingsherry
📛 Have names
✨ Unique, special
⏳ Change over time
🚑 Require bespoke care
❤ Kept alive when they are ill
PETS
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry
📛 Have names
✨ Unique, special
⏳ Change over time
🚑 Bespoke care
❤ Kept alive when they are ill
Pandas
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea
📹 High profile media coverage

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@tweetingsherry
Pet PROBLEMS
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
24/7

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry@tweetingsherry @wearebase @passengerteam

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@tweetingsherry@tweetingsherry @wearebase @passengerteam
CHALLENGE ACCEPTED

27. .
@tweetingsherry

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@tweetingsherry
$ ssh user@host -vvvvvvvvv
$ curl <url> -vvvvvvvvvvvv
$ ping 1.2.3.4
$ nmap

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry
I HAVE NO MEMORY OF THIS PLACE

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@tweetingsherry
177 cd /etc/nginx/sites-enabled/
178 ll
179 cd ..
180 cd sites-available/
181 ll
182 vim ~/.ssh/authorized_keys
183 cat /root/.ssh/
184 cat /root/.ssh/authorized_keys
185 history|less
$ history|less

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@tweetingsherry
101 tail -f /opt/logs/nginx-error.log
102 vim /etc/nginx/sites-enabled/blog.conf
...
185 history|less
$ history|less

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@tweetingsherry
101 tail -f /opt/logs/nginx-error.log
102 vim /etc/nginx/sites-enabled/blog.conf
...
185 history|less
$ history|less

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@tweetingsherry
93 service nginx restart
94 service php7.0-fpm
95 service php7.0-fpm restart
...
185 history|less
$ history|less

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@tweetingsherry

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@tweetingsherry
93 service nginx restart
94 service php7.0-fpm
95 service php7.0-fpm restart
$ history|less
$ !93
$ service nginx restart

39. .
@tweetingsherry
$ ls -l /home

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@tweetingsherry
drwxrwxrwt root root root
drwxr-xr-x+ web web web
drwxr-xr-x+ admin sudoers admin
$ sudo su web
$ ls -l /home

41. .
@tweetingsherry https://medium.com/@adminstoolbox/debugging-using-strace-efda7d65be1d

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@tweetingsherry https://medium.com/@adminstoolbox/debugging-using-strace-efda7d65be1d

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@tweetingsherry
$ pidof nginx

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@tweetingsherry
$ pidof nginx
20306 20304

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@tweetingsherry
$ pidof nginx
20306 20304
$ strace -p 20304 -p 20306 -f

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@tweetingsherry
$ pidof nginx
20306 20304
$ strace -p 20304 -p 20306 -f
inet_addr("81.27.88.19")
"GET / HTTP/1.1rn
stat(“/var/www/site.com/current/web/index.php"
writev(4, [{"HTTP/1.1 301 Moved Permanentlyrn"

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@tweetingsherry
$ pidof php-fpm
20434 20435

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@tweetingsherry
$ pidof php-fpm
20434 20435
$ strace -p 20304 -p 20306 -f

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@tweetingsherry
$ pidof php-fpm
20434 20435
$ strace -p 20304 -p 20306 -f
access("/var/www/config/prod.php", F_OK) = 0
access("/var/www/config/clients/operator.php",
F_OK) = -1 ENOENT (No such file or directory)

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@tweetingsherry
$ strace php cron.php

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@tweetingsherry
$ strace php cron.php
open("/etc/php/7.0/cli/php.ini", O_RDONLY) = 3
open("/etc/php/7.0/cli/conf.d/10-pdo.ini", O_RDONLY) = 3
open("/var/log/newrelic/php_agent.log", O_WRONLY|O_CREAT|
O_APPEND, 0666) = 3
connect(4, {sa_family=AF_LOCAL, sun_path="/
tmp/.newrelic.sock"}, 22) = 0

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@tweetingsherry
$ top
$ htop

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@tweetingsherry
$ lsof
sshd 985 root 6u TCP *:22
mongod 988 mongodb 6u TCP 127.0.0.1:27017
php-fpm7. 10546 root 8u TCP 127.0.0.1:9000
nginx 20304 root 8u TCP *:80
nginx 20304 root 9u TCP *:443

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@tweetingsherry
NOT ENOUGH SPACE

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@tweetingsherry
$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 487M 4.0K 487M 1% /dev
tmpfs 100M 376K 100M 1% /run
/dev/vda1 100G 100G 4.0B 100% /

56. .
@tweetingsherry
$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 487M 4.0K 487M 1% /dev
tmpfs 100M 376K 100M 1% /run
/dev/vda1 100G 100G 4.0B 100% /

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@tweetingsherry
$ df -h
Filesystem Size Used Avail Use% Mounted on
udev 487M 4.0K 487M 1% /dev
tmpfs 100M 376K 100M 1% /run
/dev/vda1 100G 100G 4.0B 100% /
$ rm -rf /var/cache/apt/archives
$ rm -rf /var/cache
$ ls -l /tmp
$ ls -l /var/log

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry
$ fallocate -l 4G /swapfile
$ chmod 600 /swapfile
$ mkswap /swapfile
$ swapon /swapfile

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry
MariaDB > show variables like
“max_connections”
+—————————————————+———————+
| Variable_name | Value |
+—————————————————+———————+
| max_connections | 151 |
+—————————————————+———————+

68. .
@tweetingsherry
MariaDB >
set global max_connections = 200;
+—————————————————+———————+
| Variable_name | Value |
+—————————————————+———————+
| max_connections | 200 |
+—————————————————+———————+

69. .
@tweetingsherry
vim /etc/mysql/conf.d/mysql.cnf
[mysql]
max_connections = 200

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea@tweetingsherry

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@tweetingsherry https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea@tweetingsherry

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@tweetingsherry
mysql>
SET GLOBAL slow_query_log = ‘ON’;

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@tweetingsherry
mysql>
SET GLOBAL slow_query_log = ‘ON’;
⚠
DO NOT LEAVE THIS
RUNNING IN PRODUCTION!

76. .
@tweetingsherry
mysql>
SET GLOBAL slow_query_log = ‘ON’;
/var/lib/mysql/production-slow.log

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@tweetingsherry
mysql>
SET GLOBAL slow_query_log = ‘ON’;
/var/lib/mysql/production-slow.log

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@tweetingsherry
mysql>
SET GLOBAL
log_queries_not_using_indexes
= ‘ON’;

79. .
@tweetingsherry
Reading mysql slow query log from /var/lib/mysql/
production-slow.log
Count:414 Time: 28.98s Lock: 0.00s Rows_sent 1.0,
Rows_examined: 1456 Rows_affected: 0
Count:1 Time: 2.00s Lock: 0.00s Rows_sent 1.0,
Rows_examined: 1 Rows_affected: 0
$ mysqldumpslow -a production-slow.log

80. .
@tweetingsherry
INDEX ALL THE THINGS

81. .
@tweetingsherry
Indexes
$ mysql> desc users;

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@tweetingsherry
Indexes
$ mysql> desc users;

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@tweetingsherry
Cardinality
$ mysql> show index from users;

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@tweetingsherry
Cardinality
$ mysql> show index from users;

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@tweetingsherry
QUERY ORDER
$ mysql> explain select first_name from user_profiles
where date_of_birth < “2018—01-01” and first_name like “chris%”

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@tweetingsherry
QUERY ORDER
$ mysql> explain select first_name from user_profiles
where date_of_birth < “2018—01-01” and first_name like “chris%”

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry https://medium.com/@Jay_Jamison/pets-cattle-and-pandas-30aad4a0cdea

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@tweetingsherry
DISCOUNT CODE: DAVE15

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry

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@tweetingsherry
git reset —hard ~100
git branch -D feature/work-in-progress

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@tweetingsherry
GIF OF REFLOG

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@tweetingsherry
GIF OF REFLOG

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@tweetingsherry
GIF OF REFLOG

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@tweetingsherry
GIF OF REFLOG

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@tweetingsherry
git habits

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@tweetingsherry
git habits
git commit -am “message”

111. .
@tweetingsherry
git habits
git commit -am “message”
git add .

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@tweetingsherry
git habits
git commit -am “message”
git add .
git commit

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@tweetingsherry
git habits
git commit -am “message”
git add .
git commit
git add -p (--pick)

114. .
@tweetingsherry
git habits
git commit -am “message”
git add .
git commit
git add -p (--pick)
git push --force-with-lease

115. .
@tweetingsherry
git habits
git commit -am “message”
git add .
git commit
git add -p (--pick)
git push --force-with-lease
git merge --no-commit