Does anyone know if the incremental save works on D3/NT?

System Release Information
==========================
D3 Release Version 7.4.6.NT

Implementation. . . . . . NT
Software Serial Number. . 11031251
System ID Number . . . .
Release . . . . . . . . . D3
Windows Information . . . WindowsNT;pick0;5.2.3790;;5.2

Boot Monitor. . . . . . . 7.4.6.0390; 12/23/05
Boot ABS. . . . . . . . . 7.4.6.A15; 05 Dec 2005
Boot ABS Data File. . . . 7.4.6.A15; 05 Dec 2005
System Data Files . . . . 7.4.6.D15; 05 Dec 2005
FlashBASIC Revision . . . 7.4.5.F13; 28 Apr 2005
SQL Revision. . . . . . . 7.4.5.S8; 28 Apr 2005
ABS Patch Level . . . . . no patches loaded


I was testing this out today by performing an incremental save of our
data account.
SAVE (F,I,T,U

I got a 9GB pseudo file! Our nightly backup is 13GB. There is no way
we dirtied 9GB of data since last nights save. Also, I checked and we
are not using the V option to keep items marked as dirty after the
save.

I am confused.

Cliff

Cliff,

Incremental save saves the file control block for every file, like the full
save, but only saves records with "dirty" bits showing they've changed. So
there is a lot of data saved. And it does save all changes since last full
save when dirty bits were cleared. And, if you created a workfile, filled
it with data and then cleared it, all that info would have to be saved, the
fact that they were updated and the fact that they were cleared. So that
means the incremental save also saves deletes.

That doesn't explain the large results, but if this is your 'data account',
just how many records do you change every day?

Theoretically this is all to leave you after a full restore, incremental
restore, txlog restore, right where you were just prior to the crash.

Did you try to t-read the save tape? Can you show me a page or two? Just
curious.

Also, did you start with a new p-floppy item? The save process does not
shorten the length of p-floppies, so if it's 9GB, but you only save 1GB, it
will still be 9GB to Windows. Try either deleting the item via Windows
before the save, or create a totally new item via DEV-MAKE.

Mark Brown


"Cliff" <cponce (AT) easternmetal (DOT) com> wrote

Cliff wrote:
[snip]
Cliff, don't know why your incr-save is so big, but does anyone know
what the difference is between the D and V save options? Here is what
REF has to say:

d Prevents the clearing of dirty bits. Note that this option
should only be used when performing a save in preparation for a
full restore.

v Performs a "full" file-save, but does not "unmark" the items
that have been changed. These items will continue to be saved on
subsequent incremental file-saves. Unless the "i" or "u"
options are specified, the system does a "full" file-save.


BTW, I have noticed that if you are not using incremental saves, it
makes sense to set-incremental-off (in user-coldstart) so that deletes
are actually removed from the group, instead of just marked as deleted;
files are smaller, less overflow, faster selects, etc.

/Scott Ballinger
Pareto Corporation
Edmonds WA USA
206 713 6006

Scott,

Thanks for the "set-incremental-off " tip , which I've never used (or
even recall reading about - but it is there in REF)

Likewise, I've never used incremental backups. We do a backup to
protect against disaster, and when a disaster DOES strike, we want/need
to get up & running again as quickly as possible.

With an incremental backup, it will take me LONGER to get my system
back up & functional (restore last good backup, THEN restore from the
incremental) following a disaster event. I believe that if you are
backing up to a pseudo-tape the overhead of doing a full save (vs
incremental) isn't that great, as the system has to visit every group
anyway (OK - so you don't have to traverse the linked frame list), and
provided you have a big enough time window to perform a full save [buy
bigger hardware, or a hot backup machine if you don't have the time] I
would do that EVERY time

Cliff,

How are you doing the full saves in the first place ... perhaps it
isn't resetting dirty-bits when finished !?