[lkml]   [2008]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH][RFC][BUG] updating the ctime and mtime time stamps in msync()
On Wed, 09 Jan 2008 18:41:41 EST, Rik van Riel said:

> I guess a third possible time (if we want to minimize the number of
> updates) would be when natural syncing of the file data to disk, by
> other things in the VM, would be about to clear the I_DIRTY_PAGES
> flag on the inode. That way we do not need to remember any special
> "we already flushed all dirty data, but we have not updated the mtime
> and ctime yet" state.
> Does this sound reasonable?

Is it possible that a *very* large file (multi-gigabyte or even bigger database,
for example) would never get out of I_DIRTY_PAGES, because there's always a
few dozen just-recently dirtied pages that haven't made it out to disk yet?

Of course, getting a *consistent* backup of a file like that is quite the
challenge already, because of the high likelyhood of the file being changed
while the backup runs - that's why big sites often do a 'quiesce/snapshot/wakeup'
on a database and then backup the snapshot...

[unhandled content-type:application/pgp-signature]
 \ /
  Last update: 2008-01-10 21:51    [W:0.130 / U:16.832 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site