ftpfs (was: Re: HD cloning)

Daniel Ridge newt at scyld.com
Fri Dec 15 14:37:42 PST 2000


On Fri, 15 Dec 2000, Timm Murray wrote:

> A while back, I got an idea for an 'ftpfs', literaly mounting an FTP
> store as a regular file system.  I wasn't sure if this had ever been 
> tried before, and I'm still not sure how many other OSes have it.
> However, I recently started playing with GNU HURD and learned 
> that it does have an ftpfs!  The code for it is apparently old
> (1997 was the last change log entry) and the maintainer has since
> left the FSF.
> Would an ftpfs work better then NFS (security, speed, reliability, 
> etc.)?  Are there currenly any patches for such a thing for Linux?  
> Please note that I have just started using the HURD, so I don't
> know too much about it.
> Donald Becker wrote on 12/5/00 12:34 pm:

Linux used to have a project (that I believe is now defunct) called
'userfs' that allowed for the construction of user-space filesystems.

One of the sample personalities was an FTP filesystem. I tried it
(I had other interests in userfs at the time) and was nonplussed.

All file operations would block until the entire file was retreived
and cached in a sleazy way.

Don's essential point about NFS was that it was a major serialization
point and that we could build an entire system -- if we were a bit careful
-- without needing a shared filesystem at all (for the core OS).

We've done exactly that. There were a number of cases where we could have
hacked things together quickly if we allowed ourselves to depend on
a global fs namespace.

By not depending on a shared FS at all, users and app developers have a 
completely free hand to run whatever they want with the confidence that
it won't foul us up.

An analogy is that we want to make cluster nodes as simple to manage as
SCSI attached storage. SCSI disks will hold your bits, but you must make
decisions about how the bits get laid down.

	Dan Ridge
	Scyld Computing Corporation

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