Troubleshooting

The following link is good for understanding how to (mainly designed for OS issues but can include networking/mysql bits)
In some cases rather than just copy someone else's work i link directly to their site.

Some of these may be duplicated in other areas but this page has been designed as a dumping ground for troubleshooting scripts/tips....

A

B
boot issues

C
crond dead but subsys locked
error cannot execute argument list too long (for rm,cp,mv)
check route of an ip address

D

E
disable cron emails

F
file permission are messed up

G

H
high load and no obvious cause - what else to consider

I

J

K

L

M
where has my memory gone

N
Nfs troubleshooting

O

P
performance problems & partitioning https://blog.mayflower.de/353-Is-MySQL-partitioning-useful-for-very-big-real-life-problems.html
find more information on a process
check open php connections

Q

R
fixing/restarting replication
How do reboot a troublesome machine
recover deleted files using lsof

S
slow queries/queries taking to long
slow speed of website

T
tracing a process
troubleshooting approach

U

V

W
whats writing to disk

X

Y

Z