> On Fri, 2005-06-10 at 16:04 -0400, David Boyes wrote: > > FDR physical dumps will not capture data Linux caches in memory > Ah, light comes on. > I saw your statement that an idle system is not good enough for a > consistent backup, and that a LVM snapshot is required. I guess that > snapshot flushes the cache?
Yep, as best it can. > How is that different (other than elapsed > time) from a sync followed by idling the system? sync is basically advisory, a "do this if you can" sort of thing (which is the source of the historic ritual BSD "sync;sync;sync;reboot" mantra). Also, unless you take the system to single-user mode (at which point you might as well have shut down), you've still got some background stuff going on with logging, etc, so you can't get the system to completely idle (unless you tolerate data loss in logs, and/or are willing to run fsck on everything after restoring it). The LVM snapshot tries to get everything to a consistent point, make the snap shot, and then continues on about it's business, leaving you a essentially "offline" copy that nothing is actually updating. You can dump that fairly safely. It (LVM snapshots) are still not as good as a Linux-based backup client strategy, but it's better than just physical dumps. ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
