FastDFS深入应用详解及分布式集群配置

起始

• 从应用层面详解fastdfs各组件

• fastdfs的多服务器场景使用及部署配置说明

 

相关的文章

1、单体安装教程 https://blog.csdn.net/suoyanming/article/details/88797360

2、开源中国fastdfs主页 p/fastdfs

3、github主页（不确定是否是原作者维护） happyfish100/fastdfs

4、对fastdfs-nginx-module 实现原理讲的非常清楚 https://www.cnblogs.com/littleatp/p/4361318.html     

 

一、FastDFS

1、FastDFS是一个开源的轻量级分布式文件系统，它对文件进行管理，功能包括：文件存储、文件同步、文件访问（文件上传、文件下载）等，解决了大容量存储和负载均衡的问题。特别适合以文件为载体的在线服务，如相册网站、视频网站等等。

2、FastDFS为互联网量身定制，充分考虑了冗余备份、负载均衡、线性扩容等机制，并注重高可用、高性能等指标，使用FastDFS很容易搭建一套高性能的文件服务器集群提供文件上传、下载等服务。

二、深入认识FastDFS

•      任何一个中间件的应用，都必须深入了解该中间件内部各组件的承担的功能角色、运行机制，能深入了解各组件的实现原理更好。这样才能灵活应对实际应用场景、多变的业务需求、生产环境应急等问题，快速实施架构调整。
•      我们一直在使用FastDFS作为图片文件数据库，部署架构为单体（即：一个tracker、一个storage、一个group）,由于本次用于部署fastdfs的服务器硬盘空间报警，当务之急必须更改fastdfs部署架构，扩展存储。
•      下面从项目总体情况、tracker 、storage、fastdfs-nginx-module 、group 组件详细说明其功能角色及运行机制

1、项目总体情况

•        fastdfs是开源的项目
•        通过github源码可看出，该项目是基于C语言开发的
•        fastdfs是基于操作系统OS的文件管理系统功能之上进行分布式文件管理（Linux、FreeBSD等），通过看文件在硬盘的保存方式也可以得出
•        提供C、Java和PHP API接口

2、tracker跟踪器

•  主要做调度工作， 起负载均衡的作用

•  在内存中记录集群中所有存储组group和存储服务器storage 的状态信息, 是客户端和数据服务器交互的枢纽

• tracker的核心工作内容：

          （1） 记录集群中有多少个group（group1\group2....）

            (2)  每个group 分布在那个几个storage上，以及storage所在机器的ip，端口等信息，group之间的同步由tracker 和storage一起完成（后面细讲）

          （3）如果同一个group 存在多个storage, 而这些storage又被分布在一台或多台机器上，那么对该group上传或读取文件具体落到那个机器上（即那个storage）？（有点绕）

                   tracker完美的解决了这个问题，即对分布式部署架构下：多group、多storage的上传和下载做负载均衡策略，通过配置tracker.conf可实现具体负载均衡策略

            (4)  tracker 可部署多台，多个tracker在服务器内存中记录的信息是一样的，通过nginx对tracker做负载均衡，以提高并发性能及容灾能力

          （5）tracker 不去主动读取storage的相关信息，而是由storage主动推送给tracker （这也是为什么必须先启动tracker的原因） 

          （6）以下图片摘自网上 ： 上传文件过程 、下载文件过程，通过图片可以看到，tracker的核心工作是为客户端找到一个storage, client客户端和storage进行上传下载通信。

• tracker.conf  (在分布式部署架构下，通过tracker负载均衡给client端返回特定storage信息，而负载均衡的策略配置主要在tracker.conf中)

•  1）核心参数配置说明

（1）disabled=false

         #配置文件是否失效

         # is this config file disabled

        # false for enabled

        # true for disabled disabled=false

        # is this config file disabled # false for enabled # true for disabled

（2）port=22122

           #服务端口

           # the tracker server port

（3） base_path=/data/fastdfs/tracker

             # 存放track 数据及日志文件目录 

             # the base path to store data and log files

（4）work_threads=4

 

          #时线程数：一般和cpu的个数设为同一个值         

          # work thread count, should <= max_connections

          # default value is 4

           # since V2.00

（4）（重要） store_lookup=1 

             #  上传文件选择哪个一个group 的 策略：0：轮询；1:指定组  ； 2： 负载均衡，选择剩余存储空间最大的组group 上传文件

              # the method of selecting group to upload files

             # 0: round robin

             # 1: specify group

            # 2: load balance, select the max free space group to upload file

（5）（重要） store_group=group2

        # 当  store_lookup=1  时，该配置有效，指定存储的组名

         # which group to upload file

         # when store_lookup set to 1, must set store_group to the group name

（6）（重要） store_server=0

       # 应用场景： 存在多个相同的组，例如group1 ， 在多个storage 服务器上 例如：192.168.0.171 、，

                            当上传文件时优先选择那个storage的策略配置：~ 0：轮询 ；1：按ip升序排序后选择第一个ip，即最小的那个ip (192.168.0.164)；2：按优先级排列的第一个服务器顺序，数字越小优先级越 高，storage服务器的优先在storage.conf中配置 upload_priority 参数

    # which storage server to upload file

       # 0: round robin (default)

        # 1: the first server order by ip address

        # 2: the first server order by priority (the minimal)

（7）（重要）  store_path=0

       # 应用场景：选择具体一个组的那一条存储路径（一个group有多条存储路径，一般一个服务器有两块大硬盘挂载到了两个路径下，专门用来存放文件），~0：轮询，2：负载均衡，选择剩余空间最大的路径 

         （逻辑~重要） 通过上面的配置参数确定了3件事的基础上，该配置才会起作用：

        （1）确定了要存储在那个group上，例如group1；（2）确定上传文件要保存在那一台storage 中的group1，假如是192.168.0.171；（3） 此时如果 192.168.0.171 上的storage server中group1 有两个存储路径，即store_path0,store_path1,(对应的文件路径即M00,M01)

  # which path(means disk or mount point) of the storage server to upload file

       # 0: round robin

      # 2: load balance, select the max free space path to upload file

（8）download_server=0

        # 下载文件时存储服务器的选择策略； 应用场景：要下载的文件所在group 存在多个storage 服务器上， ~0：轮询  ；1：当前文件上载到的源存储服务器

        # which storage server to download file

        # 0: round robin (default)

       # 1: the source storage server which the current file uploaded to

（9）reserved_storage_space = 10%

    # 给系统或其他应用程序预留存储空间设置 

   #（重要）场景：某一个group所在某一个storage服务器（可能存在多个服务器上）剩余的存储空间小于等于这个阀值时，则文件不能被保存，即使该group的其他storage服务器还有很大的存储空间

   # reserved storage space for system or other applications.

   # if the free(available) space of any stoarge server in

   # a group <= reserved_storage_space,

   # no file can be uploaded to this group.

   # bytes unit can be one of follows:

   ### G or g for gigabyte(GB)

   ### M or m for megabyte(MB)

   ### K or k for kilobyte(KB)

   ### no unit for byte(B)

   ### XX.XX% as ratio such as reserved_storage_space = 10%

3、storage 存储服务器

• storage 定期向tracker发送心跳，报告自己的状态，tracker会将同组的 storage server信息返回给storage （该部分逻辑后面再细讲） 

• tracker不负责具体的文件上传、下载实现，这些都是有storage完成的

• storage保存文件和文件的属性

• storage server是基于操作系统的文件管理系统进行文件管理的（上面有提到）

• group之间文件同步由storage server 和tacker server一起完成的（该部分逻辑后面再细讲） 

• storage server的状态（7个）

• FDFS_STORAGE_STATUS_INIT :初始化，尚未得到同步已有数据的源服务器

• FDFS_STORAGE_STATUS_WAIT_SYNC :等待同步，已得到同步已有数据的源服务器

• FDFS_STORAGE_STATUS_SYNCING :同步中

• FDFS_STORAGE_STATUS_DELETED :已删除，该服务器从本组中摘除（注：本状态的功能尚未实现）

• FDFS_STORAGE_STATUS_OFFLINE :离线

• FDFS_STORAGE_STATUS_ONLINE :在线，尚不能提供服务

• FDFS_STORAGE_STATUS_ACTIVE :在线，可以提供服务

storage.conf 核心参数配置

（1）port=23000

      # storage 服务端口

     # the storage server port

（2）base_path=/usr/local/fastdfs/fdfs_storage

      #存放storage 服务的数据和日志

      # the base path to store data and log files

（3）store_path0=/usr/local/fastdfs/fdfs_storage

      # 存储路径配置，可以配置多个，对应的  store_path_count=1 参数需要累加

      # store_path#, based 0, if store_path0 not exists, it's value is base_path

      # the paths must be exist

      #store_path1=/home/yuqing/fastdfs2

（4）tracker_server=192.168.0.171:22122

     #tracker 服务的 ip和端口， ip替换为域名也可以，可以配置多个 

     # tracker_server can ocur more than once, and tracker_server format is

     #  "host:port", host can be hostname or ip address

（5）file_distribute_path_mode=0

   # 分布式存储文件策略： 当storage下有多个存储路径时，该配置起作用  ~  # 0: 轮询     # 1: 根据文件名hash结果随机存储

   # the mode of the files distributed to the data path

   # 0: round robin(default)

   # 1: random, distributted by hash code  

（6）upload_priority=10 （在tracker.conf 中有提到）

# 上传文件事，同组内的storage 服务器优先级设置，且当 tracker.conf 中store_server= 2时 起作用，值越小，优先级越高。

# the priority as a source server for uploading file.

# the lower this value, the higher its uploading priority.

# default value is 10

4、group

 

•  group 分组是fastdfs应对大流量应用系统中处理高并发、高容灾的经典设计，并且group还起到了应用隔离的功能
•  一个group可以存在多个storage中（在storage中也可以提到）
• 根据client端的请求分配到不同的group，文件系统具备直接的负载均衡；
• group内有storage服务节点坏掉时，需从其他group内恢复数据  

5、 fastdfs-nginx-module 

• fastdfs 中storage、tracker 均提供的http服务，可以直接下载文件，但考虑到性能及负载实现难易度的问题，一般都用web服务器来下载文件，例如nginx、apache
• fastdfs-nginx-module 就是fastdfs基于ngnix实现文件http传输的组件，以nginx module的方式添加到nginx 程序中
• 每个storage 均需安装  fastdfs-nginx-module 、Nginx ，当前storage找不到文件时，向源storage主机发起redirect重定向或proxy转发代理动作
• fastdfs-nginx-module 安装后目录结构如下图

      说明及图片 摘自：https://www.cnblogs.com/littleatp/p/4361318.html        

          (1)ngx_http_fastdfs_module.c    ~ nginx 模块接口实现文件，用于向nginx 接入fastdfs-module核心模块逻辑

       （2）common.c   ~ fastdfs-module核心模块，实现了初始化、文件下载的主要逻辑

       （3）config     ~ 编译模块所用的配置，里面定义了一些重要的常量，调用fastdfs基础组件功能，以及扩展配置文件路径、文件下载chunk大小

 

 

   （4）mod_fastdfs.conf  ~扩展配置文件的demo，一般会将该文件拷贝到config指定的目录下 例如：/etc/fdfs

• 初始化： nginx启动时，  fastdfs-nginx-module 要完成初始化如下图 ，我们一般在mod_fastdfs.conf配置参数，如下图

（重要）： fastdfs-nginx-module 初始化的过程要加载mod_fastdfs.conf参数，如果本机器下存在多个storage,且有多个group（group1、group2）,则 mod_fastdfs.conf 配置需做如下变动

 

（1）组名：group_name=group1/group2     多个用/区分开

（2）设置组个数：group_count = 4

（4）设置各group信息：

[group1]

group_name=group1

storage_server_port=23000

store_path_count=1

store_path0=/usr/local/fastdfs/storage

[group2]

group_name=group2

storage_server_port=23010

store_path_count=1

store_path0=/usr/local/fastdfs/storage

（重要）通过nginx 从fastdfs下载文件，详细说明可参考https://www.cnblogs.com/littleatp/p/4361318.html     

6、各组件运行机制总结(重要)

•         一个group 对应多个 storage (1:N)

•        一个storage对应一个group   (1:1)

•        一个tracker对应多个storage(1:N)

•        一个storage对应多个tracker(1:N)  , tracker 和storage的关系是多对多（N:M）

•        一个storage下有多个存储路径 store_path(1:N)

7、部署架构汇总

1）单体部署: 单group\单storage\单tracker

2）单服务器多storage部署（在实际生产环境中没有意义）

 多group\多storage\单tracker

3）多服务器多group且group不互备，单tracker（我们项目本次硬盘扩展部署架构）

     由于目前服务器资源紧缺暂不做group互备，后面需要做group互备

•   部署步骤及参数配置

  （1）两台服务器分别为192.168.0.171、192.168.0.164， 171服务器担任的功能角色更多一些: 文件下载请求 nginx同一入口（分发到storage1、stroage2）、tracker server  、storage1 - group0（fastdfs-nginx-module）。

              164服务器主要负责storage1 -group2 的存储、下载功能，没有tacker server，直接连接171服务器的tracker,需要安装nginx 、 fastdfs-nginx-module

         （2) 171、 164 都需要安装 fastdfs 、fastdfs-nginx-module、 nginx  安装步骤 与  知识库文档  Centos7 上安装 FastDFS 一致 ，但注意一点164服务器不用启动及配置tracker

        （ 3） 171 tracker.conf 配置

      171 tracker.conf 核心参数配置说明，其他参数见附件

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

# is this config file disabled # false for enabled # true for disabled disabled=false   # the tracker server port port=22122   # the base path to store data and log files base_path=/data/fastdfs/tracker   # the method of selecting group to upload files # 0: round robin # 1: specify group # 2: load balance, select the max free space group to upload file store_lookup=1   # which group to upload file # when store_lookup set to 1, must set store_group to the group name store_group=group2   # which storage server to upload file # 0: round robin (default) # 1: the first server order by ip address # 2: the first server order by priority (the minimal) store_server=0   # which path(means disk or mount point) of the storage server to upload file # 0: round robin # 2: load balance, select the max free space path to upload file store_path=0     # which storage server to download file # 0: round robin (default) # 1: the source storage server which the current file uploaded to download_server=0   # reserved storage space for system or other applications. # if the free(available) space of any stoarge server in # a group <= reserved_storage_space, # no file can be uploaded to this group. # bytes unit can be one of follows: ### G or g for gigabyte(GB) ### M or m for megabyte(MB) ### K or k for kilobyte(KB) ### no unit for byte(B) ### XX.XX% as ratio such as reserved_storage_space = 10% reserved_storage_space = 10%

 

（4）171 storage.conf 配置

 

171 storage 核心参数配置，其他参数见附件

# the name of the group this storage server belongs to # # comment or remove this item for fetching from tracker server, # in this case, use_storage_id must set to true in tracker.conf, # and storage_ids.conf must be configed correctly. group_name=group0     # the storage server port port=23000     # the base path to store data and log files base_path=/data/fastdfs/storage     # path(disk or mount point) count, default value is 1 store_path_count=1     # store_path#, based 0, if store_path0 not exists, it's value is base_path # the paths must be exist store_path0=/data/fastdfs/storage #store_path1=/home/yuqing/fastdfs2     # tracker_server can ocur more than once, and tracker_server format is #  "host:port", host can be hostname or ip address tracker_server=192.168.0.171:22122     # the priority as a source server for uploading file. # the lower this value, the higher its uploading priority. # default value is 10 upload_priority=10

 

（5）171 fastdfs_nginx_module 配置参数 （mod_fastdfs.conf）

 

171 mod_fastdfs.conf 核心参数配置，其他参数见附件

# the base path to store log files base_path=/data/fastdfs/storage     # if load FastDFS parameters from tracker server # since V1.12 # default value is false load_fdfs_parameters_from_tracker=true     # FastDFS tracker_server can ocur more than once, and tracker_server format is #  "host:port", host can be hostname or ip address # valid only when load_fdfs_parameters_from_tracker is true tracker_server=192.168.0.171:22122     # the port of the local storage server # the default value is 23000 storage_server_port=23000         # the group name of the local storage server group_name=group0 # if the url / uri including the group name # set to false when uri like /M00/00/00/xxx # set to true when uri like ${group_name}/M00/00/00/xxx, such as group1/M00/xxx # default value is false url_have_group_name = true # path(disk or mount point) count, default value is 1 # must same as storage.conf store_path_count=1 # store_path#, based 0, if store_path0 not exists, it's value is base_path # the paths must be exist # must same as storage.conf store_path0=/data/fastdfs/storage #store_path1=/home/yuqing/fastdfs1         # set the group count # set to none zero to support multi-group # set to 0  for single group only # groups settings section as [group1], [group2], ..., [groupN] # default value is 0 # since v1.14 group_count = 0         # group settings for group #1 # since v1.14 # when support multi-group, uncomment following section #[group1] #group_name=group1 #storage_server_port=23000 #store_path_count=2 #store_path0=/home/yuqing/fastdfs #store_path1=/home/yuqing/fastdfs1   # group settings for group #2 # since v1.14 # when support multi-group, uncomment following section as neccessary #[group2] #group_name=group2 #storage_server_port=23000 #store_path_count=1 #store_path0=/home/yuqing/fastdfs

 

（6）171 nginx 参数配置 nginx.conf 

171 nginx.conf 核心参数配置，详见附件

events {     worker_connections  1024; } http {         include       mime.types;         default_type  application/octet-stream;     sendfile        on;         #tcp_nopush     on;         #keepalive_timeout  0;         keepalive_timeout  65;         #gzip  on;     # 192.168.0.164 storage group2      upstream fdfs_group2_164 {          server 192.168.0.164:8288 weight=1 max_fails=2 fail_timeout=30s;      }       server {                 listen       8070;                 server_name  localhost,192.168.0.171;             #charset koi8-r;             #access_log  logs/host.access.log  main;               location / {                         root   html;                         max_ranges 1;                         index  index.html index.htm;                 }              location /group0/M00{                         root /data/fastdfs/storage/data;                         ngx_fastdfs_module;                         if ($request_method = 'OPTIONS') {                                 add_header 'Access-Control-Allow-Origin' '*';                                 add_header 'Access-Control-Allow-Headers' 'Range';                                add_header 'Content-Type' 'text/plain charset=UTF-8';                                 add_header 'Content-Length' 0;                                 return 204;              }                         if ($request_method = 'POST') {                                 add_header 'Access-Control-Allow-Origin' '*';                                 add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';                                 add_header 'Access-Control-Allow-Headers' 'Range';              }                         if ($request_method = 'GET') {                                 add_header 'Access-Control-Allow-Origin' '*';                                 add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';                                 add_header 'Access-Control-Allow-Headers' 'Range';                                 add_header 'Access-Control-Expose-Headers' 'Accept-Ranges, Content-Encoding, Content-Length, Content-Range';              }                   if ($arg_attname ~* \.(doc|docx|txt|pdf|zip|rar|txt|jpg|png|gif|bmp)$) {                 add_header "Content-Disposition" "attachment;filename=$arg_attname";                     }                     }              location ~* /group2/(M00|M01) {                   proxy_next_upstream http_502 http_504 error timeout invalid_header;                  proxy_pass http://fdfs_group2_164;                 expires 30d;              }              error_page   500 502 503 504  /50x.html;                 location = /50x.html {             root   html;         }     }

 

（7）164 storage参数配置

164 storage.con 核心参数配置，其他参数见附件

# the name of the group this storage server belongs to # # comment or remove this item for fetching from tracker server, # in this case, use_storage_id must set to true in tracker.conf, # and storage_ids.conf must be configed correctly. group_name=group2         # the storage server  port port=23000     # the base path to store data and log files base_path=/usr/local/fastdfs/fdfs_storage     # path(disk or mount point) count, default value is 1 store_path_count=1 # store_path#, based 0, if store_path0 not exists, it's value is base_path # the paths must be exist store_path0=/usr/local/fastdfs/fdfs_storage #store_path1=/home/yuqing/fastdfs2     # tracker_server can ocur more than once, and tracker_server format is #  "host:port", host can be hostname or ip address tracker_server=192.168.0.171:22122     # the priority as a source server for uploading file. # the lower this value, the higher its uploading priority. # default value is 10 upload_priority=10

 

（8） 164 fastdfs_nginx_module 参数配置 （mod_fastdfs.conf）

 

164 mod_fastdfs.conf 核心参数配置，其他参数见附件

# the base path to store log files base_path=/usr/local/fastdfs/     # if load FastDFS parameters from tracker server # since V1.12 # default value is false load_fdfs_parameters_from_tracker=true         # FastDFS tracker_server can ocur more than once, and tracker_server format is #  "host:port", host can be hostname or ip address # valid only when load_fdfs_parameters_from_tracker is true tracker_server=192.168.0.171:22122 # the port of the local storage server # the default value is 23000 storage_server_port=23000     # the group name of the local storage server group_name=group2         # if the url / uri including the group name # set to false when uri like /M00/00/00/xxx # set to true when uri like ${group_name}/M00/00/00/xxx, such as group1/M00/xxx # default value is false url_have_group_name = true       # path(disk or mount point) count, default value is 1 # must same as storage.conf store_path_count=1 # store_path#, based 0, if store_path0 not exists, it's value is base_path # the paths must be exist # must same as storage.conf store_path0=/usr/local/fastdfs/fdfs_storage #store_path1=/home/yuqing/fastdfs1         # set the group count # set to none zero to support multi-group # set to 0  for single group only # groups settings section as [group1], [group2], ..., [groupN] # default value is 0 # since v1.14 group_count = 0

 

（9）164 nginx参数配置，nginx.conf

164 nginx.conf 参数配置，详见附件

user  www  www; worker_processes  12; error_log  /var/log/nginx/error.log;   events {     worker_connections  1024; }     http {     include       mime.types;      default_type  application/octet-stream;        client_max_body_size 10m;     sendfile        on; server {         listen       8288;         server_name  192.168.0.164,localhost;           location /group2/M00/{             root /usr/local/fastdfs/fdfs_storage/data;              ngx_fastdfs_module;         if ($request_method = 'OPTIONS') {                  add_header 'Access-Control-Allow-Origin' '*';                  add_header 'Access-Control-Allow-Headers' 'Range';                  add_header 'Content-Type' 'text/plain charset=UTF-8';                  add_header 'Content-Length' 0;                  return 204;              }              if ($request_method = 'POST') {                  add_header 'Access-Control-Allow-Origin' '*';                  add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';                  add_header 'Access-Control-Allow-Headers' 'Range';              }              if ($request_method = 'GET') {                  add_header 'Access-Control-Allow-Origin' '*';                  add_header 'Access-Control-Allow-Methods' 'GET, POST, OPTIONS';                  add_header 'Access-Control-Allow-Headers' 'Range';                  add_header 'Access-Control-Expose-Headers' 'Accept-Ranges, Content-Encoding, Content-Length, Content-Range';                     }                 if ($arg_attname ~* \.(doc|docx|txt|pdf|zip|rar|txt|jpg|png|gif|bmp)$) {                  add_header "Content-Disposition" "attachment;filename=$arg_attname";                  }          }       } }

 

4）真正分布式集群部署：多服务器多group且group间互备，多tracker