On Wed, Jul 26, 2006 at 03:04:34PM -0400, Alan Altmark wrote:
> On Wednesday, 07/26/2006 at 01:27 EST, J Leslie Turriff
> <[EMAIL PROTECTED]> wrote:
> > Okay, now, wait; are you saying that the storage device _does_ have a
> > mechanism for communicating with the Linux filesystem to determine what
> > filesystem pages are still cached in main storage and have not yet been
> > commited to external storage?
>
> No. I'm saying that an application that closes or flushes all of its open
> files and then tells the filesystem "commit the filesystem to disk" (e.g.
> sync) is then at a known point with respect to the dasd. It is free at
> that point to kick off a flashcopy via some command or utility and start
> running again.
if you are doing an fsync that data is guarnateed to be on stable
storage, yes. But that's not enough, because it is
a) not specified where on stable storage, it could for example still be
in the log of a data journaling device
b) you risk sever corruption if the filesystem metadata is not in a
coherent state, up to the point that you can't find your data
anymore despite it beeing on stable storage.
>
> Alan Altmark
> z/VM Development
> IBM Endicott
>
> ----------------------------------------------------------------------
> 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
---end quoted text---
----------------------------------------------------------------------
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
