PHP无法从NFS共享中读取会话

我将PHP会话文件存储在NFS共享上。问题是，PHP总是创建一个空的会话文件，但不能读/写它，所以为每个页面重新加载一个新文件创建。

如果我将会话存储路径移动到本地文件夹，会话将正常保存。另外，我正在运行具有相同配置的另一个环境，它工作得很好。

在PHP有这个问题的同一服务器上，我能够在会话保存的相同目录中创建/写/读文件(与root，非root和www-data用户进行测试)。

我使用PHP 5.5.12, Apache 2.4.9和NFS v3在Ubuntu 12.04 LTS

我的php . ini中

session.save_handler = files
session.save_path = "2;/mnt/cache/sessions"
session.use_cookies = 1
session.use_only_cookies = 0
session.name = PHPSESSID
session.auto_start = 0
session.cookie_lifetime = 2592000
session.cookie_path = /
session.cookie_domain =
session.cookie_httponly =
session.serialize_handler = php
session.gc_probability = 1
session.gc_divisor = 1000
session.gc_maxlifetime = 2592000
session.bug_compat_42 = Off
session.bug_compat_warn = Off
session.referer_check =
session.entropy_length = 0
session.cache_limiter = nocache
session.cache_expire = 180
session.use_trans_sid = 0
session.hash_function = 0
session.hash_bits_per_character = 5

nfs-srv.local:/export/cache   /mnt/cache   nfs    rw,hard,intr  0  0

我/etc/exports nfs-srv.local

/export/cache 10.1.10.0/24(rw,nohide,insecure,no_subtree_check,async,all_squash,anonuid=33,anongid=33)

ls /mnt/cache/sessions/ -l
drwxrwxrwx 34 nobody nogroup 4096 May 16 10:33 0
drwxrwxrwx 34 nobody nogroup 4096 May 16 10:33 1
drwxrwxrwx 34 nobody nogroup 4096 May 16 10:33 2
...
ls /mnt/cache/sessions/m -l
drwxrwxrwx 2 nobody nogroup 4096 May 16 10:33 0
drwxrwxrwx 2 nobody nogroup 4096 May 16 12:18 1
drwxrwxrwx 2 nobody nogroup 4096 May 16 10:33 2
drwxrwxrwx 2 nobody nogroup 4096 May 16 10:33 3
drwxrwxrwx 2 nobody nogroup 4096 May 16 12:16 4
drwxrwxrwx 2 nobody nogroup 4096 May 16 12:14 5
...
ls /mnt/cache/sessions/m/5 -l
-rw------- 1 nobody nogroup 0 May 16 12:14 sess_m5ifehvhkjdisp7dgtiuu601e2