NFS缓存清理命令? [英] NFS cache-cleaning command?

问题描述

我在使用NFS客户端属性缓存时遇到了麻烦. 我正在使用一些服务器，一个是NFS服务器，其他是NFS客户端服务器.

I have a trouble with NFS client-side attribute caching. I'm using some servers, one is an NFS server and the others are NFS client servers.

所有服务器均为Debian(Linux的lenny，2.6.26-2-amd64)，并且版本如下.

All servers are Debian(lenny, 2.6.26-2-amd64 of Linux) and versions are following.

 % dpkg -l | grep nfs
ii  libnfsidmap2                        0.20-1                     An nfs idmapping library
ii  nfs-common                          1:1.1.2-6lenny1            NFS support files common to client and server
ii  nfs-kernel-server                   1:1.1.2-6lenny1            support for NFS kernel server

在NFS服务器中，/etc/exports编写如下:

In the NFS server, /etc/exports is written as following:

/export-path   192.168.0.0/255.255.255.0(async,rw,no_subtree_check)

在NFS客户端中，/etc/fstab编写如下:

In the NFS clients, /etc/fstab is written as following:

server:/export-path     /mountpoint   nfs rw,hard,intr,rsize=8192,async 0 0

如您所见，异步"选项用于多客户端访问性能. 但是，有时这可能会导致错误缓存错误.

As you can see, "async" option is used for multi-clients access performance. However, sometimes this can cause false-caching errors.

由于我要维护许多服务器(并且我没有改变安装选项的强烈权限)，所以我不想修改/etc/exports或/etc/fstab. 我认为只要有一个命令行工具就可以使用用户权限清理" NFS客户端属性缓存，就足够了.

Since I am maintaining many servers (and I have not so strong permission to change the mount options), I don't want to modify /etc/exports nor /etc/fstab. I think it is sufficient if I have a command-line tool that "cleans" NFS client-side attribute cache with a user permission.

请告诉我是否有这样的命令.

Please let me know if there such commands.

谢谢

---

(附加)

我的意思是错误缓存错误"，

I mean by "false-caching errors",

 % ls -l /data/1/kabe/foo                  
ls: cannot access /data/1/kabe/foo: No such file or directory
 % ssh another-server 'touch /data/1/kabe/foo' 
 % ls -l /data/1/kabe/foo
ls: cannot access /data/1/kabe/foo: No such file or directory

有时会发生这种情况. 问题不是文件内容，而是文件属性(=牙科信息)，因为NFS表示它可以保证从打开到打开"的一致性.

Sometimes such cases happen. The problem is not a file content but file attributes(=dentries information) since NFS says it guarantees Close-to-Open consistency.

推荐答案

根据您所说的错误缓存错误"，运行sync可能会满足您的需求.这将刷新所有文件系统缓冲区.

Depending on what you mean by "false-caching errors", running sync may get you what you need. This will flush all filesystem buffers.

如果需要，还可以使用/proc/sys/vm/drop_caches清除内核中的VM缓存.

If needed, you can also clear out the VM caches in the kernel using /proc/sys/vm/drop_caches.

# To free pagecache
echo 1 > /proc/sys/vm/drop_caches

# To free dentries and inodes
echo 2 > /proc/sys/vm/drop_caches

# To free pagecache, dentries and inodes
echo 3 > /proc/sys/vm/drop_caches

这篇关于NFS缓存清理命令?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！