route命令参数详细说明及常用命令
原文地址 docs.lvrui.io
> route
Kernel IP routing table
Destination Gateway Genmask Flags Metric Ref Use Iface
default localhost 0.0.0.0 UG 100 0 0 eno16780032
172.17.0.0 0.0.0.0 255.255.0.0 U 0 0 0 docker0
192.168.10.0 0.0.0.0 255.255.255.0 U 100 0 0 eno16780032
macOS 中使用 netstat -nr 命令来查看当前路由表
简单的讲讲nginx+php的一些常用优化，以及相关的内核参数优化。
UNIX 域套接字提供的性能略高于 TCP 套接字在回送接口上的性能（较少的数据复制，较少的上下文切换）。如果每个服务器需要支持超过 1000 个连接，请使用 TCP 套接字 - 它们可以更好地扩展。
...修改supervisord配置突破1024最大连接数
最近在使用supervisord服务时发现，无论如何修改系统的最大连接数，由supervisord管理的程序都无法突破1024的限制。
...Too many open files、获取不到$HOME等
vim /etc/supervisord.conf
[supervisord]
minfds=81920
minprocs=81920
# systemctl restart supervisord
[program:apache2]
command=/home/chrism/bin/httpd -c "ErrorLog /dev/stdout" -DFOREGROUND
user=chrism
environment=HOME="/home/chrism",USER="chrism"
supervisorctl update
使用deviceQuery获取显卡信息
Linux、nvidia、cuda
/usr/local/cuda/extras/demo_suite/deviceQuery
CUDA Device Query (Runtime API) version (CUDART static linking)
Detected 2 CUDA Capable device(s)
Device 0: "GeForce RTX 2080 Ti"
CUDA Driver Version / Runtime Version 10.1 / 10.1
CUDA Capability Major/Minor version number: 7.5
Total amount of global memory: 11019 MBytes (11554717696 bytes)
(68) Multiprocessors, ( 64) CUDA Cores/MP: 4352 CUDA Cores
GPU Max Clock rate: 1545 MHz (1.54 GHz)
Memory Clock rate: 7000 Mhz
Memory Bus Width: 352-bit
L2 Cache Size: 5767168 bytes
Maximum Texture Dimension Size (x,y,z) 1D=(131072), 2D=(131072, 65536), 3D=(16384, 16384, 16384)
Maximum Layered 1D Texture Size, (num) layers 1D=(32768), 2048 layers
Maximum Layered 2D Texture Size, (num) layers 2D=(32768, 32768), 2048 layers
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 49152 bytes
Total number of registers available per block: 65536
Warp size: 32
Maximum number of threads per multiprocessor: 1024
Maximum number of threads per block: 1024
Max dimension size of a thread block (x,y,z): (1024, 1024, 64)
Max dimension size of a grid size (x,y,z): (2147483647, 65535, 65535)
Maximum memory pitch: 2147483647 bytes
Texture alignment: 512 bytes
Concurrent copy and kernel execution: Yes with 3 copy engine(s)
Run time limit on kernels: No
Integrated GPU sharing Host Memory: No
Support host page-locked memory mapping: Yes
Alignment requirement for Surfaces: Yes
Device has ECC support: Disabled
Device supports Unified Addressing (UVA): Yes
Device supports Compute Preemption: Yes
Supports Cooperative Kernel Launch: Yes
Supports MultiDevice Co-op Kernel Launch: Yes
Device PCI Domain ID / Bus ID / location ID: 0 / 1 / 0
Compute Mode:
< Default (multiple host threads can use ::cudaSetDevice() with device simultaneously) >
Device 1: "GeForce RTX 2080 Ti"
CUDA Driver Version / Runtime Version 10.1 / 10.1
CUDA Capability Major/Minor version number: 7.5
Total amount of global memory: 11019 MBytes (11554717696 bytes)
(68) Multiprocessors, ( 64) CUDA Cores/MP: 4352 CUDA Cores
GPU Max Clock rate: 1545 MHz (1.54 GHz)
Memory Clock rate: 7000 Mhz
Memory Bus Width: 352-bit
L2 Cache Size: 5767168 bytes
Maximum Texture Dimension Size (x,y,z) 1D=(131072), 2D=(131072, 65536), 3D=(16384, 16384, 16384)
Maximum Layered 1D Texture Size, (num) layers 1D=(32768), 2048 layers
Maximum Layered 2D Texture Size, (num) layers 2D=(32768, 32768), 2048 layers
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 49152 bytes
Total number of registers available per block: 65536
Warp size: 32
Maximum number of threads per multiprocessor: 1024
Maximum number of threads per block: 1024
Max dimension size of a thread block (x,y,z): (1024, 1024, 64)
Max dimension size of a grid size (x,y,z): (2147483647, 65535, 65535)
Maximum memory pitch: 2147483647 bytes
Texture alignment: 512 bytes
Concurrent copy and kernel execution: Yes with 3 copy engine(s)
Run time limit on kernels: No
Integrated GPU sharing Host Memory: No
Support host page-locked memory mapping: Yes
Alignment requirement for Surfaces: Yes
Device has ECC support: Disabled
Device supports Unified Addressing (UVA): Yes
Device supports Compute Preemption: Yes
Supports Cooperative Kernel Launch: Yes
Supports MultiDevice Co-op Kernel Launch: Yes
Device PCI Domain ID / Bus ID / location ID: 0 / 2 / 0
Compute Mode:
< Default (multiple host threads can use ::cudaSetDevice() with device simultaneously) >
> Peer access from GeForce RTX 2080 Ti (GPU0) -> GeForce RTX 2080 Ti (GPU1) : Yes
> Peer access from GeForce RTX 2080 Ti (GPU1) -> GeForce RTX 2080 Ti (GPU0) : Yes
deviceQuery, CUDA Driver = CUDART, CUDA Driver Version = 10.1, CUDA Runtime Version = 10.1, NumDevs = 2
https://github.com/NVIDIA/cuda-samples/tree/master/Samples/deviceQuery
...因为需要mediainfo支持http协议，在老的版本中是不支持的，所以只能自己动手编译了。
系统：ubuntu 14.04 (其他版本可能会有少许改动)
...收集一些ssh登陆常见的问题，方便快速解决问题。
cat /var/log/secure
cat /var/log/message
无论你遇到任何奇葩的sshd问题，你先执行上面的命令查看下日志。
Authentication refused:bad ownership or modes for dircetory /root
chmod 700 /root
id_ras 权限为600
...使用openssl生产自签名证书，用于https测试。
#1.生成根证书密钥
$ openssl genrsa -out ca.key 4096 #建议长度为4096,1024长度已经被列为不安全。
#2.生成自签名根证书
$ openssl req -new -x509 -days 3650 -key ca.key -out ca.crt #这里在输入CommonName的时候输入名称而不是域名或者ip,就是证书上显示的颁发者，虽然是自签名证书，但是尽量让证书看起来标准一些
$ openssl genrsa -out server.key 4096
高版本的Chrome浏览器会要求设置 subjectAltName,如果没有设置SAN会报证书错误
centos自带的repo是不会自动更新每个软件的新版本，所以无法通过yum方式安装MySQL的高版本，所以一般通过社区rpm包安装。
rpm -Uvh http://dev.mysql.com/get/mysql-community-release-el7-5.noarch.rpm
yum repolist enabled | grep "mysql.*-community.*"
yum -y install mysql-community-server
systemctl enable mysqld
systemctl start mysqld
mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MySQL
SERVERS IN PRODUCTION USE! PLEASE READ EACH STEP CAREFULLY!
In order to log into MySQL to secure it, we'll need the current
password for the root user. If you've just installed MySQL, and
you haven't set the root password yet, the password will be blank,
so you should just press enter here.
Enter current password for root (enter for none):
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
Enter current password for root (enter for none):
ERROR 1045 (28000): Access denied for user 'root'@'localhost' (using password: YES)
Enter current password for root (enter for none):
OK, successfully used password, moving on...
Setting the root password ensures that nobody can log into the MySQL
root user without the proper authorisation.
Set root password? [Y/n] y
New password:
Re-enter new password:
Password updated successfully!
Reloading privilege tables..
... Success!
By default, a MySQL installation has an anonymous user, allowing anyone
to log into MySQL without having to have a user account created for
them. This is intended only for testing, and to make the installation
go a bit smoother. You should remove them before moving into a
production environment.
Remove anonymous users? [Y/n] Y
... Success!
Normally, root should only be allowed to connect from 'localhost'. This
ensures that someone cannot guess at the root password from the network.
Disallow root login remotely? [Y/n] n
... skipping.
By default, MySQL comes with a database named 'test' that anyone can
access. This is also intended only for testing, and should be removed
before moving into a production environment.
Remove test database and access to it? [Y/n] n
... skipping.
Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.
Reload privilege tables now? [Y/n] Y
... Success!
All done! If you've completed all of the above steps, your MySQL
installation should now be secure.
Thanks for using MySQL!
Cleaning up...
Supervisor是用Python开发的一套通用的进程管理程序，能将一个普通的命令行进程变为后台daemon，并监控进程状态，异常退出时能自动重启。
...