NCACHE

• The fast web cache server base on nginx

• Use aio sendfile and epoll modules

• The self sort share mem hash index

• High performance and large storage

• Low cpu cost and low iowait

• Record lock instead of process lock

• Without http headers cache

OVERVIEWF5

NGINX PROXY

NCACHE

BACKEND BACKEND BACKEND

STRUCTURE

Be proxy

hash index

Init by Ngx master process when nginx is start on

Ngx worker process Ngx worker process

Disk Files

Read / write by file system or raw dev

Backend server Backend server

Backend server

Body filter

Get the proxy content and save into the disk by aio

Logic Diagram

Request Request

Find cache in indexfound

Not found

Timeout?

not

yes

Sendfile output

Proxy backend

Body filterWritev output

Aiowrite fresh index

The self sort share mem hash index

2(5)

3(4)

First floor of hash index

List to solve the conflict of the hash

Hash_malloc

1(6)

Index[1]+2 = 7

1(6)

3(4)

2(7)

Top:0

16777216

33554432

If arrived at the bottom of the share memory then ncache will return to the 16777216 point and find which can be reused

Record lock

Mmapauto sync

Mem index Sync file

Worker process

Worker process

Read

Write

Worker process

Do not need to lock any worker processor request

cause wait

not cause wait

not cause wait

Performance between SQUID 1

0. 00

5. 00

10. 00

15. 00

20. 00

25. 00

0:10:01

0:40:01

1:10:01

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3:40:01

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0. 001. 002. 003. 004. 005. 006. 007. 008. 009. 0010. 00

0:10:01

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First: cpu last: io Blue is ncache

Performance between SQUID 2

0. 050. 0100. 0150. 0200. 0250. 0300. 0350. 0400. 0450. 0500. 0

1 57

113

169

225

281

337

393

449

505

561

617

673

729

785

841

897

953

0. 050. 0100. 0150. 0200. 0250. 0300. 0350. 0400. 0450. 0500. 0

1 57

113

169

225

281

337

393

449

505

561

617

673

729

785

841

897

953

SQUID

NCACHE

Future

• The aio_sendfile function

• Compress share memory hash index

• Memory cache the hottest data

• Raw device read and write

• Distribute storage system

• Aio queue with lio_listio function

The end

• Google code:– http://code.google.com/p/ncache/

• Nginx wiki:– http://wiki.codemongers.com/

• Our mail:– pangfan@staff.sina.com.cn– shuiyang@staff.sina.com.cn