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Re: Live Fille System Backup

On 07/05/17 01:56, tomas@tuxteam.de wrote:
On Sat, May 06, 2017 at 06:42:46AM -0400, Dan Ritter wrote:
On Sat, May 06, 2017 at 07:52:25AM +0200, tomas@tuxteam.de wrote:
On Fri, May 05, 2017 at 01:35:35PM -0700, Sergei G wrote:
it would be naive at best to think that busy files [...]
What is a "busy" file?
Open for writing.
Hm. That just means that the file will change after being copied.
In itself not a problem (Note that there are other, stronger concepts
of busy. An open file for write can be opened for read/write by
another process, can be deleted, yadda, yadda. It can be definitely
copied. Less civilised operating systems lock files when opened for
write, but not the Unixoids).

If a file is updated while it is being copied, it may contain only half a change set and be in an internally inconsistent state, perhaps making it unusable as a backup. Writes are typically not atomic. The same problem applies to collections of files that reference each other.

Kind regards,

Ben Caradoc-Davies <ben@transient.nz>
Transient Software Limited <http://transient.nz/>
New Zealand

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