学步园

原来针对NFS4，exports需要一个新的参数fsid，
如我的exports：
/home/bee  *(rw,fsid=0,sync,no_root_squash)

fsid=num|root|uuid
             NFS
needs to  be able  to identify 
each filesystem  that  it
             exports. 
Normally it will use a UUID for thefilesystem (if the
             filesystem
has such a thing) or the device number ofthe  device
             holding 
the filesystem  (if the 
filesystem  is stored onthe
             device).

             As
not all filesystems  are stored  on devices, 
and not  all
             filesystems 
have UUIDs, it is sometimes necessaryto explicitly
             tell
NFS how to identify a filesystem.  Thisis  done 
with the
             fsid=
option.

             For
NFSv4, there is a distinguished filesystem which is theroot
             of
all exported filesystem.  This is specifiedwith fsid=root or
             fsid=0
both of which mean exactly the same thing.

             Other 
filesystems  can beidentified with a small integer, or a
             UUID
which should contain 32 hex digits and arbitrary  punctua‐
             tion.

             Linux 
kernels  version 2.6.20and earlier do not understand the