On Thu, Jan 28, 2016 at 4:12 PM, Martin Schwedhelm silo_18@... [firebird-support] <firebird-support@yahoogroups.com> wrote:

As far as I can tell (via gstat) forced write is enabled.

Also, regarding virtual machines, at least ESX(i) does not cache guest OS writes

(http://www.yellow-bricks.com/2011/04/07/mythbuster s-esxesxi-caching-io/).

OK.  There are myths about disks that lie about writing stuff, but that's way on the outer edge

of probability, especially since you've got lots of pages of zeros.

Maybe a thing that was not clear in my initial post:

We don't use a sql command that deletes that many records or drop tables.

The missing (zeroed) data should not be zeroed at all.

 When Firebird releases a page because it went empty or the table was dropped or

whatever, it doesn't zero the page.  My somewhat feeble recollection is that pages of zeros

are newly allocated and never used, or trompled by rogue processes.  

Good luck,

Ann