[Asterisk-Users] MeetMe Features

[Christopher L. Wade]

Peter Svensson wrote:
> On Fri, 10 Dec 2004, Christopher L. Wade wrote:
> 
> 
>>>I don't think I quite understand.  Even if it is on a different
>>>partition, the path should still be the same should it not?
>>>/var/spool should still work whether it is on /dev/hda2 or /dev/hda5 ?
>>>
>>
>>What he is saying here, is that a 'mv' across multiple partitions, which 
>>to the file-system, could be multiple devices, is not as simple as 
>>moving a pointer.
>>
>>For a 'mv' across partitions/disks, the file has to be 'copied' to the 
>>new location and then 'removed' from the old location.  For a 'mv' 
>>inside the same partition, the pointer in the file-system is simply 
>>changed, and you're done.  Thus a 'mv' across partitions is not atomic, 
>>and a 'mv' inside the partition is.
> 
> 
> Not so much partitions as file systems, but otherwise you are right. A
> filesystem can span multipple partitions and devices (think raid). A unix
> file system really has to guarantee that from the user space view a rename
> is an atomic operation. A rename can move a file from one location to
> antoher within the file system. No such guarantee needs to be made across
> filesystems. To give such a guarantee so would be unresonably hard (the
> data would *have* to be copied) that is not required and usually not 
> given.
> 
> Peter

[* Bow *] I over/under simplified.  You are exactly correct.

-Chris

-- 
Christopher L. Wade                     Unistar-Sparco Computers, Inc.
Senior Systems Administrator                            dba Sparco.com
Email: clwade at sparco.com                             7089 Ryburn Drive
Phone: (901) 872 2272 / (800) 840 8400            Millington, TN 38053
Fax:   (901) 872 8482                                              USA