记一次rsync在nfs环境下错误处理

公司有一应用，即利用rsync开源工具从生产机拉归档日志至备份机，rsync命令从备份机发起，实现类似ftp下载的功能，但是近期发现rsync获取归档日志的时候，发现以下错误：

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$ sudo rsync -av  --port=2008 hisdb02::mcdbra/archlog/orcl1/1_44792_698764072.dbf /tmp

receiving incremental file list
rsync: send_files failed to open "/archlog/orcl1/1_44792_698764072.dbf" (in mcdbra): Permission denied (13)

日志显示生产机无法open归档日志1_44792_698764072.dbf，进一步检查得知该归档日志存放在nfs文件系统上。

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root@hisdb02:/var/adm#df
Filesystem    512-blocks      Free %Used    Iused %Iused Mounted on
/dev/hd4         2097152   1995896    5%     2323     2% /
/dev/hd2         6815744   3685120   46%    37222     9% /usr
/dev/hd9var      2097152    178200   92%      443     3% /var
/dev/hd3        33554432  29460648   13%     1390     1% /tmp
/dev/hd1         2097152   1626432   23%      488     1% /home
/proc                  -         -    -         -     -  /proc
/dev/hd10opt     2097152   1917288    9%     2745     2% /opt
/dev/lvoracle   62914560  27519376   57%    76569     3% /oracle
/dev/fslv00   2086666240 748941176   65%      382     1% /rman
/dev/lvdbra     83886080  78608608    7%    25150     1% /dbra
/dev/lvarch    104857600  76068312   28%      370     1% /archlog/orcl2
hisdb01:/archlog/orcl1  167772160 130979864   22%     4995     1% /archlog/orcl1

但是在hisdb02主机上对目录/archlog/orcl1有读写权限，但没有赋权或者更改文件属主的权限。

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root@hisdb02:/archlog/orcl1#chown oracle:dba lll
chown: lll: Operation not permitted.

在hisdb02上检查/etc/filesystems配置文件，似乎也没有明显错误：

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/archlog/orcl1:
     dev= "/archlog/orcl1"
     vfs= nfs
     nodename= hisdb01
     mount= true
     type= nfs
     options= rw,bg,hard,intr,vers=3,rsize=32768,wsize=32768,timeo=600,proto=tcp,biods=32
     account= false

直觉告诉我，rsync出现这个错误，应该和nfs特定的权限有关，于是进一步在hisdb01上检查nfs配置文件/etc/exports,可以看到配置文件中并没有显示赋予root访问权限。

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root@hisdb01:/#cat /etc/exports
/archlog/orcl1 -rw,access=hisdb02

于是添加root显示访问权限

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root@hisdb01:/#cat /etc/exports
/archlog/orcl1 -rw,root=hisdb02,access=hisdb02

AIX对于选项的解释如下：

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rw = Client [:Client]
Exports the directory with read-write permission to the specified Clients. Exports the directory read-only to Clients not in the list. A read-write list cannot be specified if a read-only list has been specified.
                  
access = Client[:Client,...]
Gives mount access to each Client listed. If not specified, any Client is allowed to mount the specified directory
                  
root=Client[:Client]
Allows root access from the specified Clients. Clients not in the list are not allowed root access.

为保险起见在hisdb01重新exportfs -a，然后在hisdb02重新umount，mount nfs文件系统之后，问题解决。
附：
在aix上修改配置文件/etc/exports除了手工编辑之外，aix还提供smitty 接口用于修改

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root@hisdb01:/#smit chnfsexp


* Pathname of directory to export                     /archlog/orcl1
  Anonymous UID                                      [-2]
  Public filesystem?                                 [no]                                                                        +
* Change export now, system restart or both           both                                                                       +
  Pathname of alternate exports file                 []
  Allow access by NFS versions                       []
  External name of directory (NFS V4 access only)    []
  Referral locations (NFS V4 access only)            []
  Replica locations                                  []
  Ensure primary hostname in replica list             yes                                                                        +
  Allow delegations?                                 []
  Security method 1                                  [sys,none]                                                                  +
      Mode to export directory                       [read-write]                                                                +
      Hostname list. If exported read-mostly         []
      Hosts & netgroups allowed client access        [hisdb02]
      Hosts allowed root access                      [hisdb02]
  Security method 2                                  []                                                                          +
      Mode to export directory                       []                                                                          +
      Hostname list. If exported read-mostly         []
      Hosts & netgroups allowed client access        []
      Hosts allowed root access                      []
  Security method 3                                  []                                                                          +
      Mode to export directory                       []                                                                          +
      Hostname list. If exported read-mostly         []
      Hosts & netgroups allowed client access        []
      Hosts allowed root access                      []
  Security method 4                                  []                                                                          +
      Mode to export directory                       []                                                                          +
      Hostname list. If exported read-mostly         []
      Hosts & netgroups allowed client access        []
      Hosts allowed root access                      []

或者通过chnfsexp命令进行修改     

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/usr/sbin/chnfsexp -d '/archlog/orcl1' '-B' -S 'sys,none' -t 'rw' -c 'hisdb02' -r 'hisdb02'