Why do these pipes report as empty files to 'file'?
Using NFS it sets up what would *seem* to be some pipes in /var/lib/nfs/rpc_pipefs, however some of these seem to have rather odd characteristics and they confuse rdiff-backup so it reports errors due to files apparently changing while it runs. The specific files in question are these:- chris$ ls -l /var/lib/nfs/rpc_pipefs/nfs/clnt* /var/lib/nfs/rpc_pipefs/nfs/clnt6: total 0 -r-------- 1 root root 0 2009-08-25 21:42 info /var/lib/nfs/rpc_pipefs/nfs/clnt7: total 0 -r-------- 1 root root 0 2009-08-25 21:42 info /var/lib/nfs/rpc_pipefs/nfs/clnt8: total 0 -r-------- 1 root root 0 2009-08-25 21:42 info Now note that these are reported as normal (but empty) files by 'ls'. Similarly 'file' reports them the same:- chris$ file /var/lib/nfs/rpc_pipefs/nfs/clnt?/* /var/lib/nfs/rpc_pipefs/nfs/clnt6/info: empty /var/lib/nfs/rpc_pipefs/nfs/clnt7/info: empty /var/lib/nfs/rpc_pipefs/nfs/clnt8/info: empty But they're not really empty, presumably because they're pipes or fifos or something:- root@chris:/var/lib/nfs/rpc_pipefs/nfs# cat /var/lib/nfs/rpc_pipefs/nfs/clnt6/info RPC server: garage.local service: nfs (100003) version 3 address: 192.168.1.88 protocol: tcp port: 0 root@chris:/var/lib/nfs/rpc_pipefs/nfs# This is presumably what's confusing rdiff-backup because they *seem* to be empty ordinary files but they aren't. Is this normal for pipes/fifos or is there something special about these? -- Chris Green
Chris G wrote:
Using NFS it sets up what would *seem* to be some pipes in /var/lib/nfs/rpc_pipefs, however some of these seem to have rather odd characteristics and they confuse rdiff-backup Those files are not normal disk directories/files/pipes; they are provided by a separate filesystem which is used by nfs internally. So, don't backup/restore that directory.
A quick way to check for that is to use "df" on the file: root@yoda:/# df /var/lib/nfs/rpc_pipefs/nfs/clnt27/info Filesystem 1K-blocks Used Available Use% Mounted on rpc_pipefs 0 0 0 - /var/lib/nfs/rpc_pipefs You might use rdiff-backup's "--exclude-other-filesystems" to avoid surprises like this. -- Martijn
On Wed, Sep 02, 2009 at 08:39:00PM +0100, Martijn Koster wrote:
Chris G wrote:
Using NFS it sets up what would *seem* to be some pipes in /var/lib/nfs/rpc_pipefs, however some of these seem to have rather odd characteristics and they confuse rdiff-backup Those files are not normal disk directories/files/pipes; they are provided by a separate filesystem which is used by nfs internally. So, don't backup/restore that directory.
Ah, I wondered why they acted so oddly, thanks. I don't need to back them up of course but it would be a bit of a pain to deselect them specifically.
A quick way to check for that is to use "df" on the file:
root@yoda:/# df /var/lib/nfs/rpc_pipefs/nfs/clnt27/info Filesystem 1K-blocks Used Available Use% Mounted on rpc_pipefs 0 0 0 - /var/lib/nfs/rpc_pipefs
You might use rdiff-backup's "--exclude-other-filesystems" to avoid surprises like this.
Ah, if "--exclude-other-filesystems" does that then it's what I need, thank you. -- Chris Green
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Martijn Koster