V2EX › whoami9894 的所有回复 › 第 9 页 / 共 33 页

V2EX = way to explore

V2EX 是一个关于分享和探索的地方

现在注册

已注册用户请登录

1 ... 5 6 7 8 9 10 11 12 13 14 ... 33

❮

❯

2019-12-15 09:08:09 +08:00

回复了 MarkZuckerberg 创建的主题 › 问与答 › 什么软件能快速填充满硬盘的剩余空间？

Windows 的 Format 命令已经支持安全擦除整个分区。Format 命令加上 /P 参数后，就会把每个扇区先清零，再用随机数覆盖。而且可以覆盖多次。比如“format D: /P:8”就表示把 D 盘用随机数覆盖 8 次。

那如何用 Windows 自带功能在不格式化磁盘的情况下安全删除文件呢？ Cipher 命令本来是用于磁盘加密的，但有个 /W 参数可对磁盘上未使用的空间进行覆盖。比如你刚刚删除了 D:\Private 目录下的几个文件，那么执行一下“cipher /w:D:\Private”。D 盘上未使用空间就会被覆盖三次：一次 0x00、一次 0xFF，一次随机数。所有被删除的文件就都不可能被恢复了。

转自 tk 教主围脖

2019-11-18 17:34:12 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@ClericPy
学到了，感谢感谢

2019-11-18 16:22:31 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@ClericPy
Time per request: 1311.422 [ms] (mean)
Time per request: 1.311 [ms] (mean, across all concurrent requests)
我搜了下超过 1s 应该是 1000 并发量都请求一次的时间，平均下来一个请求 1ms 左右，应该差不多

2019-11-18 16:17:15 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@chenset 果然是，改成 2^16-1 感觉没啥问题了

```
Concurrency Level: 1000
Time taken for tests: 13.114 seconds
Complete requests: 10000
Failed requests: 421
(Connect: 0, Receive: 0, Length: 421, Exceptions: 0)
Total transferred: 24437163 bytes
HTML transferred: 20628743 bytes
Requests per second: 762.53 [#/sec] (mean)
Time per request: 1311.422 [ms] (mean)
Time per request: 1.311 [ms] (mean, across all concurrent requests)
Transfer rate: 1819.74 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 188 724 226.3 670 2185
Processing: 118 540 146.4 538 1997
Waiting: 22 232 137.8 188 1775
Total: 465 1265 265.6 1234 2689

Percentage of the requests served within a certain time (ms)
50% 1234
66% 1315
75% 1370
80% 1409
90% 1538
95% 1703
98% 2100
99% 2193
100% 2689 (longest request)
```

2019-11-18 13:33:45 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@phpdever
`-c 1000 -n 3000`时的负载情况

```
top - 13:30:23 up 51 days, 16:50, 2 users, load average: 1.67, 0.46, 0.18
任务: 269 total, 3 running, 197 sleeping, 0 stopped, 0 zombie
%Cpu(s): 72.1 us, 7.5 sy, 0.0 ni, 18.5 id, 0.0 wa, 0.0 hi, 1.9 si, 0.0 st
KiB Mem : 16422300 total, 1691276 free, 1062368 used, 13668656 buff/cache
KiB Swap: 2097148 total, 2097148 free, 0 used. 15068552 avail Mem

进 USER PR NI VIRT RES SHR %CPU %MEM TIME+ COMMAND 22322 root 20 0 120432 72864 11844 R 496.3 0.4 5:00.33 main
11740 root 20 0 115144 75736 5228 R 98.7 0.5 0:04.26 ab
4207 mysql 20 0 4790288 291612 15756 S 44.9 1.8 31:01.26 mysqld
```

```
Concurrency Level: 1000
Time taken for tests: 4.461 seconds
Complete requests: 3000
Failed requests: 2677
(Connect: 0, Receive: 0, Length: 2677, Exceptions: 0)
Total transferred: 6918669 bytes
HTML transferred: 5772209 bytes
Requests per second: 672.43 [#/sec] (mean)
Time per request: 1487.146 [ms] (mean)
Time per request: 1.487 [ms] (mean, across all concurrent requests)
Transfer rate: 1514.42 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 156 753 286.5 689 1852
Processing: 57 517 166.8 534 1167
Waiting: 9 243 132.5 208 904
Total: 326 1271 353.3 1284 2457

Percentage of the requests served within a certain time (ms)
50% 1284
66% 1355
75% 1384
80% 1481
90% 1696
95% 1965
98% 2169
99% 2209
100% 2457 (longest request)
```

2019-11-18 13:24:42 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@lbp0200
这是`-c 20 -n 1000`的结果

```
Concurrency Level: 20
Time taken for tests: 1.383 seconds
Complete requests: 1000
Failed requests: 0
Total transferred: 2532000 bytes
HTML transferred: 2152000 bytes
Requests per second: 723.07 [#/sec] (mean)
Time per request: 27.660 [ms] (mean)
Time per request: 1.383 [ms] (mean, across all concurrent requests)
Transfer rate: 1787.92 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 7 19 5.4 18 39
Processing: 2 8 3.9 8 27
Waiting: 1 6 3.3 5 25
Total: 10 27 6.3 27 54

Percentage of the requests served within a certain time (ms)
50% 27
66% 29
75% 30
80% 31
90% 36
95% 40
98% 45
99% 46
100% 54 (longest request)
```

2019-11-18 13:23:27 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@Flasky 不求能抗住抢课那个并发量 2333。我们教务系统每逢抢课必挂，抢课脚本得在抢课开始前维护一个 TCP 连接池

2019-11-18 13:22:17 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@ClericPy 这个接口逻辑就是从 session 里取用户名，然后 SELECT 一次数据库，这样测试我怀疑数据库缓存也有加成

我换成`-n 3000 -c 1000`结果是这样，fail 还是过多

```
Concurrency Level: 1000
Time taken for tests: 5.023 seconds
Complete requests: 3000
Failed requests: 2421
(Connect: 0, Receive: 0, Length: 2421, Exceptions: 0)
Total transferred: 6381837 bytes
HTML transferred: 5230257 bytes
Requests per second: 597.29 [#/sec] (mean)
Time per request: 1674.237 [ms] (mean)
Time per request: 1.674 [ms] (mean, across all concurrent requests)
Transfer rate: 1240.82 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 380 807 255.4 738 1678
Processing: 151 518 156.7 480 1094
Waiting: 28 264 151.7 223 830
Total: 594 1325 242.7 1277 2621

Percentage of the requests served within a certain time (ms)
50% 1277
66% 1387
75% 1457
80% 1531
90% 1642
95% 1769
98% 1994
99% 2087
100% 2621 (longest request)
```

2019-11-18 13:18:33 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@richangfan 你不说我还没注意到 90%请求都失败了.......

2019-11-18 13:17:55 +08:00

回复了 whoami9894 创建的主题 › 问与答 › 请教一下 ab 压测

@chenset 其实我不太理解的是 rps 700 是个什么级别，假如说 2000 人同时请求的话会不会就挂了

2019-11-14 18:11:19 +08:00

回复了 warmwei 创建的主题 › 程序员 › 爬虫求助：爬虫新手，请教各位大佬， CSDN 抓取文章 html 的时候返回不了正确的 html,该如何处理

HTML 由 js 动态生成的，还做了混淆

2019-11-14 18:07:38 +08:00

回复了 different 创建的主题 › Linux › 初学 socks5，想问一下 socket 的握手阶段是必须的吗？

socks5 应用层协议建立在 tcp 之上，先 tcp socket 握手建立连接，socks5 再通过这条连接发送握手包