一、查看squid命中情况
除了之前在squid的access.log中查看squid缓存命中的方法之外，还可以通过以下方法进行查看：
这里对图片服务器的httpd配置文件添加一些新的配置如下：
ExpiresActive on
ExpiresDefault "access plus 12 month"
ExpiresByType text/html "access plus 12 months"
ExpiresByType text/css "access plus 12 months"
ExpiresByType image/gif "access plus 12 months"
ExpiresByType image/jpeg "access plus 12 months"
ExpiresByType image/jpg "access plus 12 months"
ExpiresByType image/png "access plus 12 months"
ExpiresByType application/x-javascript "access plus 12 months"
ExpiresByType vedio/x-flv "access plus 12 months"
把以上内容追加到httpd.conf文件中，然后重新启动httpd服务。
1）使用curl命令查看
[root@squid ~]# curl -I -s http://192.168.49.135/lnmp.jpg
HTTP/1.0 200 OK
Date: Mon, 31 Oct 2016 03:10:20 GMT
Server: Apache/2.2.15 (CentOS)
Last-Modified: Thu, 26 Jun 2014 01:12:31 GMT
ETag: "bf742-2f37a-4fcb2e3149dc0"
Accept-Ranges: bytes
Content-Length: 193402
Content-Type: image/jpeg
Age: 22522
X-Cache: HIT from cache1.contoso.com
Via: 1.0 cache1.contoso.com (squid/3.0.STABLE20)
Connection: close
[root@squid ~]# curl -I -s http://192.168.49.135/lnmp.jpg|grep -i x-cache
X-Cache: HIT from cache1.contoso.com
[root@squid ~]# curl -I -s http://192.168.49.135/php.jpg|grep -i x-cache
X-Cache: HIT from cache1.contoso.com
[root@squid ~]# curl -I -s http://192.168.49.135/nginx.jpg|grep -i x-cache
X-Cache: HIT from cache1.contoso.com
[root@squid ~]# curl -I -s http://192.168.49.135/mysql.png|grep -i x-cache
X-Cache: HIT from cache1.contoso.com
2）使用Firefox的firebug插件进行查看
可以看到，在响应头信息中，有max-age也就是我在httpd中设置的expire时间，同样也可以在Expires看到过期时间，Server项显示web服务器的类型，这里是Apache；Via表示通过哪个代理服务器进行访问，这里是我在squid.conf中配置的名称cache1.contoso.com（后面还有squid的版本信息）；X-Cache中HIT from cache1.contoso.com表示请求内容在cache1.contoso.com上命中。
3）可能遇到的问题及原因
问题1：日志看不到命中
原因：curl的不是squid缓存服务器地址，而是web服务器，所以看不到命中。
问题2：看到的总是MISS
原因：使用了Ctrl+F5刷新，所以总是cache丢失。
问题3：是否做了服务器时间同步？
服务器时间同步会影响缓存结果，需要在服务器上进行时间同步。
二、修改squid的默认日志格式
squid默认记录日志格式如下：
logformat combined %>a %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh
修改squid配置文件，添加如下内容：
# 下面是logs相关配置
emulate_httpd_log on
logformat squid %{X-Forwarded-For}>h %ui %un [%tl] "%rm %ru HTTP/%rv" %Hs %<st "%{Referer}>h" "%{User-Agent}>h" %Ss:%Sh #修改后的access.log格式
access_log /usr/local/squid/var/logs/access.log squid
cache_log /usr/local/squid/var/logs/cache.log
cache_store_log /usr/local/squid/var/logs/store.log
logfile_rotate 20
修改完成后，重启squid服务，再进行日志的查看：
killall squid
squid -k parse
squid -D
[root@squid etc]# tail -f ../var/logs/access.log
1477907509.273 0 192.168.49.139 TCP_HIT/200 358 HEAD http://192.168.49.135/php.jpg - NONE/- image/jpeg
1477907514.597 0 192.168.49.139 TCP_HIT/200 358 HEAD http://192.168.49.135/nginx.jpg - NONE/- image/jpeg
1477907521.269 0 192.168.49.139 TCP_HIT/200 360 HEAD http://192.168.49.135/lnmp.jpg - NONE/- image/jpeg
# 上面是修改之前的日志格式，下面是修改之后的日志格式
- - - [31/Oct/2016:06:06:13 -0400] "HEAD http://192.168.49.135/lnmp.jpg HTTP/1.1" 200 360 "-" "curl/7.19.7 (x86_64-redhat-linux-gnu) libcurl/7.19.7 NSS/3.14.0.0 zlib/1.2.3 libidn/1.18 libssh2/1.4.2" TCP_HIT:NONE
- - - [31/Oct/2016:06:07:15 -0400] "GET http://192.168.49.135/lnmp.jpg HTTP/1.1" 304 250 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko" TCP_IMS_HIT:NONE
- - - [31/Oct/2016:06:07:26 -0400] "GET http://192.168.49.135/lnmp.jpg HTTP/1.1" 200 193829 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko" TCP_CLIENT_REFRESH_MISS:FIRST_UP_PARENT
- - - [31/Oct/2016:06:07:27 -0400] "GET http://192.168.49.135/lnmp.jpg HTTP/1.1" 200 193829 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko" TCP_CLIENT_REFRESH_MISS:FIRST_UP_PARENT
- - - [31/Oct/2016:06:07:30 -0400] "GET http://192.168.49.135/lnmp.jpg HTTP/1.1" 304 286 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko" TCP_IMS_HIT:NONE
- - - [31/Oct/2016:06:07:31 -0400] "GET http://192.168.49.135/lnmp.jpg HTTP/1.1" 304 286 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko" TCP_IMS_HIT:NONE
- - - [31/Oct/2016:06:07:35 -0400] "GET http://192.168.49.135/lnmp.jpg HTTP/1.1" 304 286 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko" TCP_IMS_HIT:NONE
# 修改之后的日志格式记录的信息更详细，另外时间也不再是一串看不懂的数字，更易于阅读
其中的对端编码含义如下表所示：（参考squid权威指南：http://zyan.cc/book/squid/chap13.html）
| NONE |
这指明Squid对本次请求，不会与任何其他服务器（邻居或原始服务器）通信。它通常与cache命中、拒绝请求、cache管理请求、错误、和所有的ICP查询这些类型联合出现。 |
| DIRECT |
Squid直接转发请求到原始服务器。该域的第2半部分显示原始服务器的IP地址，或主机名--假如禁止了log_ip_on_direct。 |
| SIBLING_HIT |
在姐妹cache返回ICP或HTCP命中后，Squid发送请求到姐妹cache。 |
| PARENT_HIT |
在父cache返回ICP或HTCP命中后，Squid发送请求到父cache。 |
| DEFAULT_PARENT |
Squid选择该父cache，因为其在squid.conf的cache_peer行里被标志为default。 |
| FIRST_UP_PARENT |
Squid转发请求到该父cache，因为它是位于已知活跃列表里的第一个父cache。 |
| FIRST_PARENT_MISS |
Squid转发请求到该父cache，它第一个响应ICP/HTCP丢失消息。换句话说，对这个特殊的ICP/HTCP查询，在这个特殊时刻，被选中的父cache有最佳的往返时间（RTT）。注意标准RTT可能被人工矫正过，取决于cache_peer指令的weight选项。 |
| CLOSEST_PARENT_MISS |
Squid选择该父cache，因为它报告到原始服务器的RTT最低。这点仅在2个cache都激活了netdb，并且原始服务器（或在同一子网内的其他server）返回ICMP ping消息。 |
| CLOSEST_PARENT |
这点类似CLOSEST_PARENT_MISS，除了RTT计算不是来自ICP/HTCP响应消息外。代替的，它们来自Squid保留的更老的计算方式，例如netdb交换功能。 |
| CLOSEST_DIRECT |
Squid基于netdb算法，转发请求到原始服务器。这点在满足下述任何条件时发生：
|
| ROUNDROBIN_PARENT |
Squid转发请求到该父cache，因为设置了round-robin选项，并且它有最低的使用计数器。 |
| CD_PARENT_HIT |
Squid基于cache摘要算法（见10.7节）转发请求到该父cache。 |
| CD_SIBLING_HIT |
Squid基于cache摘要算法转发请求到该姐妹cache。 |
| CARP |
Squid选择该父cache，基于cache数组路由协议算法（见10.9节）。 |
| ANY_PARENT |
作为最后的手段，Squid选择该父cache，因为没有其他方法能选择可行的下一跳。 注意大部分上述编码可能以TIMEOUT_开头，这表明在等待ICP/HTCP响应时发生超时。例如： 1066038165.382 345 193.233.46.21 TCP_MISS/200 2836
GET http://www.caida.org/home/./images/home.jpg
TIMEOUT_CLOSEST_DIRECT/213.219.122.19 image/jpeg 可使用icp_query_timeout指令来调整超时。 |
其中的结果编码含义如下表：
| TCP_HIT |
Squid发现请求资源的貌似新鲜的拷贝，并将其立即发送到客户端。 |
| TCP_MISS |
Squid没有请求资源的cache拷贝。 |
| TCP_REFERSH_HIT |
Squid发现请求资源的貌似陈旧的拷贝，并发送确认请求到原始服务器。原始服务器返回304（未修改）响应，指示squid的拷贝仍旧是新鲜的。 |
| TCP_REF_FAIL_HIT |
Squid发现请求资源的貌似陈旧的拷贝，并发送确认请求到原始服务器。然而，原始服务器响应失败，或者返回的响应Squid不能理解。在此情形下，squid发送现有cache拷贝（很可能是陈旧的）到客户端。 |
| TCP_REFRESH_MISS |
Squid发现请求资源的貌似陈旧的拷贝，并发送确认请求到原始服务器。原始服务器响应新的内容，指示这个cache拷贝确实是陈旧的。 |
| TCP_CLIENT_REFRESH_MISS |
Squid发现了请求资源的拷贝，但客户端的请求包含了Cache-Control: no-cache指令。Squid转发客户端的请求到原始服务器，强迫cache确认。 |
| TCP_IMS_HIT |
客户端发送确认请求，Squid发现更近来的、貌似新鲜的请求资源的拷贝。Squid发送更新的内容到客户端，而不联系原始服务器。 |
| TCP_SWAPFAIL_MISS |
Squid发现请求资源的有效拷贝，但从磁盘装载它失败。这时squid发送请求到原始服务器，就如同这是个cache丢失一样。 |
| TCP_NEGATIVE_HIT |
在对原始服务器的请求导致HTTP错误时，Squid也会cache这个响应。在短时间内对这些资源的重复请求，导致了否命中。negative_ttl指令控制这些错误被cache的时间数量。请注意这些错误只在内存cache，不会写往磁盘。下列HTTP状态码可能导致否定cache（也遵循于其他约束）： 204, 305, 400, 403, 404, 405, 414, 500, 501, 502, 503, 504。 |
| TCP_MEM_HIT |
Squid在内存cache里发现请求资源的有效拷贝，并将其立即发送到客户端。注意这点并非精确的呈现了所有从内存服务的响应。例如，某些cache在内存里，但要求确认的响应，会以TCP_REFRESH_HIT, TCP_REFRESH_MISS等形式记录。 |
| TCP_DENIED |
因为http_access或http_reply_access规则，客户端的请求被拒绝了。注意被http_access拒绝的请求在第9域的值是NONE/-，然而被http_reply_access拒绝的请求，在相应地方有一个有效值。 |
| TCP_OFFLINE_HIT |
当offline_mode激活时，Squid对任何cache响应返回cache命中，而不用考虑它的新鲜程度。 |
| TCP_REDIRECT |
重定向程序告诉Squid产生一个HTTP重定向到新的URI（见11.1节）。正常的，Squid不会记录这些重定向。假如要这样做，必须在编译squid前，手工定义LOG_TCP_REDIRECTS预处理指令。 |
| NONE |
无分类的结果用于特定错误，例如无效主机名。 相应于ICP查询，下列标签可能出现在access.log文件的第四域。 |
| UDP_HIT |
Squid在cache里发现请求资源的貌似新鲜的拷贝。 |
| UDP_MISS |
Squid没有在cache里发现请求资源的貌似新鲜的拷贝。假如同一目标通过HTTP请求，就可能是个cache丢失。请对比UDP_MISS_NOFETCH。 |
| UDP_MISS_NOFETCH |
跟UDP_MISS类似，不同的是这里也指示了Squid不愿去处理相应的HTTP请求。假如使用了-Y命令行选项，Squid在启动并编译其内存索引时，会返回这个标签而不是UDP_MISS。 |
| UDP_DENIED |
因为icp_access规则，ICP查询被拒绝。假如超过95%的到某客户端的ICP响应是UDP_DENIED，并且客户端数据库激活了（见附录A），Squid在1小时内，停止发送任何ICP响应到该客户端。若这点发生，你也可在cache.log里见到一个警告。 |
| UDP_INVALID |
Squid接受到无效查询（例如截断的消息、无效协议版本、URI里的空格等）。Squid发送UDP_INVALID响应到客户端。 |
三、查看squid缓存文件情况
squidclient -h localhost -p 80 mgr:objects
这个命令能知道如下重要信息：
1、打印出的是所有缓存在内存和硬盘上的数据，对象是以key来表示，每个key代表不同的对象。
2、列出对象是否存放在内存，还是硬盘。
IN_MEMORY 在内存中
命令执行结果示例：
[root@squid etc]# squidclient -h localhost -p 80 mgr:objects
HTTP/1.0 200 OK
Server: squid/3.0.STABLE20
Mime-Version: 1.0
Date: Mon, 31 Oct 2016 13:33:30 GMT
Content-Type: text/plain
Expires: Mon, 31 Oct 2016 13:33:30 GMT
Last-Modified: Mon, 31 Oct 2016 13:33:30 GMT
X-Cache: MISS from cache1.contoso.com
Via: 1.0 cache1.contoso.com (squid/3.0.STABLE20)
Connection: close
KEY 9C60DB2318E2EB2A91411D99F2EDD2C0
STORE_OK IN_MEMORY SWAPOUT_NONE PING_NONE
SPECIAL,CACHABLE,VALIDATED
LV:1477908352 LU:1477908352 LM:1476530330 EX:-1
0 locks, 0 clients, 0 refs
Swap Dir -1, File 0XFFFFFFFF
GET http://cache1.contoso.com/squid-internal-static/icons/anthony-image.gif
inmem_lo: 0
inmem_hi: 452
swapout: 0 bytes queued
KEY B44033DA692B451D4ED732876ECB50AC
STORE_OK NOT_IN_MEMORY SWAPOUT_DONE PING_NONE
CACHABLE,DISPATCHED,VALIDATED
LV:1476808880 LU:1476808880 LM:1476773657 EX:-1
0 locks, 0 clients, 1 refs
Swap Dir 0, File 0X0001DF
KEY B5C0B572C5A3971F66058A0096D49366
STORE_OK NOT_IN_MEMORY SWAPOUT_DONE PING_NONE
CACHABLE,DISPATCHED,VALIDATED
LV:1476654128 LU:1476736902 LM:1473492811 EX:1508190128
0 locks, 0 clients, 1 refs
Swap Dir 0, File 0X000119
KEY B9406F5E8C58201286101BE33EBE58FF
STORE_OK NOT_IN_MEMORY SWAPOUT_DONE PING_NONE
CACHABLE,DISPATCHED,VALIDATED
LV:1460859669 LU:1476751308 LM:1459827216 EX:1492395669
0 locks, 0 clients, 1 refs
Swap Dir 0, File 0X000162
KEY C400A8CBAF19FB0C8A768B638D2E53CB
STORE_OK IN_MEMORY SWAPOUT_DONE PING_DONE
CACHABLE,DISPATCHED,VALIDATED
LV:1477908447 LU:1477908456 LM:1403745151 EX:1509012447
0 locks, 0 clients, 5 refs
Swap Dir 0, File 0X000198
GET http://192.168.49.135/lnmp.jpg
inmem_lo: 0
inmem_hi: 193735
swapout: 193735 bytes queued
KEY E720447A2A98968C2673DD228AEADFC7
STORE_OK IN_MEMORY SWAPOUT_NONE PING_NONE
SPECIAL,CACHABLE,VALIDATED
LV:1477908352 LU:1477908352 LM:1476530331 EX:-1
0 locks, 0 clients, 0 refs
Swap Dir -1, File 0XFFFFFFFF
GET http://cache1.contoso.com/squid-internal-static/icons/anthony-xpm.gif
inmem_lo: 0
inmem_hi: 393
swapout: 0 bytes queued
KEY 63C142B374127C8B784BC7F5AE4DD63C
STORE_OK NOT_IN_MEMORY SWAPOUT_DONE PING_NONE
CACHABLE,DISPATCHED,VALIDATED
LV:1476589869 LU:1476636053 LM:1476589526 EX:-1
0 locks, 0 clients, 1 refs
Swap Dir 0, File 0X000024
KEY 88C1A24267886989BC04C47A1484B4DA
STORE_OK IN_MEMORY SWAPOUT_NONE PING_NONE
SPECIAL,CACHABLE,VALIDATED
LV:1477908352 LU:1477908352 LM:1476530331 EX:-1
0 locks, 0 clients, 0 refs
Swap Dir -1, File 0XFFFFFFFF
GET http://cache1.contoso.com/squid-internal-static/icons/anthony-unknown.gif
inmem_lo: 0
inmem_hi: 388
swapout: 0 bytes queued
其他查看缓存的相关命令：
取得squid运行状态信息：squidclient -p 80 mgr:info
取得squid内存使用情况：squidclient -p 80 mgr:mem
取得squid已经缓存的列表：squidclient -p 80 mgr:objects
取得squid的磁盘使用情况：squidclient -p 80 mgr:diskd
常用的查看请求的命令：
squidclient -h localhost -p 80 mgr:5min
squidclient -h localhost -p 80 mgr:5min |egrep "client_http.requests|client_http.hits"
squidclient -h localhost -p 80 mgr:mem
squidclient -h localhost -p 80 mgr:info
[root@squid etc]# squidclient -h localhost -p 80 mgr:5min
HTTP/1.0 200 OK
Server: squid/3.0.STABLE20
Mime-Version: 1.0
Date: Mon, 31 Oct 2016 13:53:10 GMT
Content-Type: text/plain
Expires: Mon, 31 Oct 2016 13:53:10 GMT
Last-Modified: Mon, 31 Oct 2016 13:53:10 GMT
X-Cache: MISS from cache1.contoso.com
Via: 1.0 cache1.contoso.com (squid/3.0.STABLE20)
Connection: close
sample_start_time = 1477921689.217542 (Mon, 31 Oct 2016 13:48:09 GMT)
sample_end_time = 1477921989.280484 (Mon, 31 Oct 2016 13:53:09 GMT)
client_http.requests = 0.006665/sec
client_http.hits = 0.000000/sec
client_http.errors = 0.000000/sec
client_http.kbytes_in = 0.000000/sec
client_http.kbytes_out = 0.013331/sec
client_http.all_median_svc_time = 0.000000 seconds
client_http.miss_median_svc_time = 0.000000 seconds
client_http.nm_median_svc_time = 0.000000 seconds
client_http.nh_median_svc_time = 0.000000 seconds
client_http.hit_median_svc_time = 0.000000 seconds
server.all.requests = 0.000000/sec
server.all.errors = 0.000000/sec
server.all.kbytes_in = 0.000000/sec
server.all.kbytes_out = 0.000000/sec
server.http.requests = 0.000000/sec
server.http.errors = 0.000000/sec
server.http.kbytes_in = 0.000000/sec
server.http.kbytes_out = 0.000000/sec
server.ftp.requests = 0.000000/sec
server.ftp.errors = 0.000000/sec
server.ftp.kbytes_in = 0.000000/sec
server.ftp.kbytes_out = 0.000000/sec
server.other.requests = 0.000000/sec
server.other.errors = 0.000000/sec
server.other.kbytes_in = 0.000000/sec
server.other.kbytes_out = 0.000000/sec
icp.pkts_sent = 0.000000/sec
icp.pkts_recv = 0.000000/sec
icp.queries_sent = 0.000000/sec
icp.replies_sent = 0.000000/sec
icp.queries_recv = 0.000000/sec
icp.replies_recv = 0.000000/sec
icp.replies_queued = 0.000000/sec
icp.query_timeouts = 0.000000/sec
icp.kbytes_sent = 0.000000/sec
icp.kbytes_recv = 0.000000/sec
icp.q_kbytes_sent = 0.000000/sec
icp.r_kbytes_sent = 0.000000/sec
icp.q_kbytes_recv = 0.000000/sec
icp.r_kbytes_recv = 0.000000/sec
icp.query_median_svc_time = 0.000000 seconds
icp.reply_median_svc_time = 0.000000 seconds
dns.median_svc_time = 0.000000 seconds
unlink.requests = 0.000000/sec
page_faults = 0.000000/sec
select_loops = 196.805376/sec
select_fds = 0.026661/sec
average_select_fd_period = 0.000000/fd
median_select_fds = 0.000000
swap.outs = 0.000000/sec
swap.ins = 0.000000/sec
swap.files_cleaned = 0.000000/sec
aborted_requests = 0.000000/sec
syscalls.disk.opens = 0.000000/sec
syscalls.disk.closes = 0.000000/sec
syscalls.disk.reads = 0.000000/sec
syscalls.disk.writes = 0.000000/sec
syscalls.disk.seeks = 0.000000/sec
syscalls.disk.unlinks = 0.000000/sec
syscalls.sock.accepts = 0.013331/sec
syscalls.sock.sockets = 0.000000/sec
syscalls.sock.connects = 0.000000/sec
syscalls.sock.binds = 0.000000/sec
syscalls.sock.closes = 0.006665/sec
syscalls.sock.reads = 0.006665/sec
syscalls.sock.writes = 0.013331/sec
syscalls.sock.recvfroms = 0.000000/sec
syscalls.sock.sendtos = 0.000000/sec
cpu_time = 1.622753 seconds
wall_time = 300.062942 seconds
cpu_usage = 0.540804%
[root@squid etc]# squidclient -h localhost -p 80 mgr:5min |egrep "client_http.requests|client_http.hits"
client_http.requests = 0.009998/sec
client_http.hits = 0.000000/sec
[root@squid etc]# squidclient -h localhost -p 80 mgr:mem
HTTP/1.0 200 OK
Server: squid/3.0.STABLE20
Mime-Version: 1.0
Date: Mon, 31 Oct 2016 13:55:18 GMT
Content-Type: text/plain
Expires: Mon, 31 Oct 2016 13:55:18 GMT
Last-Modified: Mon, 31 Oct 2016 13:55:18 GMT
X-Cache: MISS from cache1.contoso.com
Via: 1.0 cache1.contoso.com (squid/3.0.STABLE20)
Connection: close
Current memory usage:
Pool Obj SizeChunksAllocated In UseIdleAllocations Saved Hit Rate
(bytes)KB/ch obj/ch(#) used free part %Frag (#) (KB) high (KB) high (hrs) %Tot(#) (KB) high (KB) high (hrs) %alloc(#) (KB) high (KB)(#) %cnt %vol(#) / sec
Total 1 0 0 0 0 0 0 -1 0 0 0 4.1e+05 -1 0 0 0 4.1e+05 -1 0 0 0 0 -1 -1 0
Cumulative allocated volume: 0.00 MB
Current overhead: 752 bytes (-1%)
Idle pool limit: 5 MB
Total Pools created: 94
Pools ever used: 94 (shown above)
Currently in use: 0
String Pool Impact
(%strings) (%volume)
Short Strings 97 97
Medium Strings 0 0
Long Strings 0 0
Other Strings 3 3
Large buffers: 0 (0 KB)
[root@squid etc]# squidclient -h localhost -p 80 mgr:info
HTTP/1.0 200 OK
Server: squid/3.0.STABLE20
Mime-Version: 1.0
Date: Mon, 31 Oct 2016 13:52:19 GMT
Content-Type: text/plain
Expires: Mon, 31 Oct 2016 13:52:19 GMT
Last-Modified: Mon, 31 Oct 2016 13:52:19 GMT
X-Cache: MISS from cache1.contoso.com
Via: 1.0 cache1.contoso.com (squid/3.0.STABLE20)
Connection: close
Squid Object Cache: Version 3.0.STABLE20
Start Time:Mon, 31 Oct 2016 10:05:52 GMT
Current Time:Mon, 31 Oct 2016 13:52:19 GMT
Connection information for squid:
Number of clients accessing cache:3
Number of HTTP requests received:16
Number of ICP messages received:0
Number of ICP messages sent:0
Number of queued ICP replies:0
Number of HTCP messages received:0
Number of HTCP messages sent:0
Request failure ratio: 0.00
Average HTTP requests per minute since start:0.1
Average ICP messages per minute since start:0.0
Select loop called: 8245010 times, 1.648 ms avg
Cache information for squid:
Hits as % of all requests:5min: 0.0%, 60min: 0.0%
Hits as % of bytes sent:5min: 100.0%, 60min: 100.0%
Memory hits as % of hit requests:5min: 0.0%, 60min: 0.0%
Disk hits as % of hit requests:5min: 0.0%, 60min: 0.0%
Storage Swap size:16992 KB
Storage Swap capacity:16.6% used, 83.4% free
Storage Mem size:296 KB
Storage Mem capacity: 0.3% used, 99.7% free
Mean Object Size:25.32 KB
Requests given to unlinkd:3
Median Service Times (seconds) 5 min 60 min:
HTTP Requests (All): 0.00000 0.00000
Cache Misses: 0.00000 0.00000
Cache Hits: 0.00000 0.00000
Near Hits: 0.00000 0.00000
Not-Modified Replies: 0.00000 0.00000
DNS Lookups: 0.00000 0.00000
ICP Queries: 0.00000 0.00000
Resource usage for squid:
UP Time:13587.130 seconds
CPU Time:42.919 seconds
CPU Usage:0.32%
CPU Usage, 5 minute avg:0.55%
CPU Usage, 60 minute avg:0.56%
Process Data Segment Size via sbrk(): 3680 KB
Maximum Resident Size: 104608 KB
Page faults with physical i/o: 0
Memory usage for squid via mallinfo():
Total space in arena: 3812 KB
Ordinary blocks: 3673 KB 7 blks
Small blocks: 0 KB 0 blks
Holding blocks: 37528 KB 6 blks
Free Small blocks: 0 KB
Free Ordinary blocks: 138 KB
Total in use: 41201 KB 100%
Total free: 138 KB 0%
Total size: 41340 KB
Memory accounted for:
Total accounted: 0 KB 0%
memPool accounted: 0 KB 0%
memPool unaccounted: 41340 KB 100%
memPoolAlloc calls: 0
memPoolFree calls: 0
File descriptor usage for squid:
Maximum number of file descriptors: 64000
Largest file desc currently in use: 18
Number of file desc currently in use: 13
Files queued for open: 0
Available number of file descriptors: 63987
Reserved number of file descriptors: 100
Store Disk files open: 0
Internal Data Structures:
697 StoreEntries
27 StoreEntries with MemObjects
26 Hot Object Cache Items
671 on-disk objects
查看squid命中率：cat /usr/local/squid/var/logs/access.log |awk '{print $4}' |sort |uniq -c|sort -nr
[root@squid etc]# cat /usr/local/squid/var/logs/access.log.1 |awk '{print $4}' |sort |uniq -c|sort -nr
26854 TCP_MISS/200
831 TCP_MISS/503
455 TCP_MISS/304
390 TCP_MISS/404
153 TCP_MISS/504
77 TCP_CLIENT_REFRESH_MISS/200
50 TCP_DENIED/403
35 TCP_REFRESH_UNMODIFIED/304
21 TCP_MISS/302
20 TCP_MISS/000
16 TCP_MISS/502
12 TCP_MISS/206
9 TCP_MISS/403
6 TCP_REFRESH_MODIFIED/200
1 TCP_CLIENT_REFRESH_MISS/000
四、清理squid缓存
1）编辑squid.conf文件，添加如下几行：
acl PURGE method PURGE #定义一个PURGE方法
http_access allow PURGE localhost #允许localhost使用PURGE方法
http_access deny PURGE #禁止其他任何服务器使用PURGE方法
2）重启squid
killall squid
squid -k parse
squid -D
3)使用squidclient命令清除squid缓存
[root@squid etc]# squidclient -m PURGE -p 80 http://192.168.49.135/lnmp.jpg
HTTP/1.0 200 OK
Server: squid/3.0.STABLE20
Mime-Version: 1.0
Date: Mon, 31 Oct 2016 14:23:02 GMT
Content-Length: 0
X-Cache: MISS from cache1.contoso.com
Via: 1.0 cache1.contoso.com (squid/3.0.STABLE20)
Connection: close
4）测试缓存是否清除成功
[root@squid etc]# curl -I -s http://192.168.49.135/lnmp.jpg
HTTP/1.0 200 OK
Date: Mon, 31 Oct 2016 14:25:33 GMT
Server: Apache/2.2.15 (CentOS)
Last-Modified: Thu, 26 Jun 2014 01:12:31 GMT
ETag: "bf742-2f37a-4fcb2e3149dc0"
Accept-Ranges: bytes
Content-Length: 193402
Cache-Control: max-age=31104000
Expires: Thu, 26 Oct 2017 14:25:33 GMT
Content-Type: image/jpeg
X-Cache: MISS from cache1.contoso.com
Via: 1.0 cache1.contoso.com (squid/3.0.STABLE20)
Connection: close
如果需要删除多个链接，可以使用shell脚本然后将链接整理到一个文件中，然后循环调用squidclient进行删除。
如果要清除全部缓存，可以先关闭squid服务，然后删除或移除cache文件夹，然后再创建cache目录并重新初始化。
squid -k shutdown
cd /usr/local/squid/var
mv cache oldcache
mkdir cache
chown squid:squid cache
squid -z
squid -s
rm -rf oldcache &
案例补充：
缓存不同步 问题如何解决？
现象：不同地区显示页面不一致
解决：在8台cache服务器手工刷新缓存，由业务部门提供有问题的URL链接。
squidclient -m purge -u squid -g squid http://
