fP and data integrity...how to maintain on non-quiescent systems?

[Mike Schwartz (PC Support & Services, Appleton, WI)]

On Sat, February 17, 2007 18:53, Fairlight wrote:
> Company X is a 24/7 business running fP.
>
> Let's look at the time it takes (figure about 20-30min) to rsync or
> tape-backup all the data between tables A and Q.  In that time, both
> tables
> may have been updated, but the detail for things that got backed up in the
> headers will be missing in your backup.
>
> This leaves you with a non-viable backup.

     On the few 24/7 applications that I've written, users never touch the
records in the master files directly.  They are always working from
some temporary filePro file or from a filePro qualifier that doesn't
need to be backed up.  Since I control when the new or modified
records get posted into the master file, I can turn off the posting
processes while I do a master file backup, then turn on the posting
to the master files after the backup completes.

     My initial backups are always hard drive to hard drive; usually to a
2nd hard drive within the same compuer box.  After this initial (very
fast) backup is done, I don't care how long it takes to dump the
files to tape or transmit them off-site via an Internet connection.

     Keeping the master data in multiple qualifiers also helps, because
each master qualifier is relatively small. For example, in one 24/7
trucking company application that I wrote around 20 years ago, when
qualified lookups first became available (filePro 4.0 ???), the
qualifiers are named for the Julian date.  IE, one qualifier is named
0107 (1st month of 2007).  Users never see these qualifier names. 
They THINK they see only one master file, but I use lookups with a
qualifier name to do all the background work.

     In one of my web based applications, I simply have users hitting a
persistent data server, instead of live files, and I log each
attempted data change for later posting, after a customer service rep
has approved the changes.

     I have several other things that I do to work around this problem, if
I haven't already gotten the wheels in your head turning...

Mike Schwartz