Subject Re: Create shadow's commit on large database locking up system until finished.
Author rpjohio
--- In, "Alan McDonald" <alan@m...>
> > Using Firebird WI-V1.5.2.4731 - when I create a shadow db
> > using "Create Shadow 1 AUTO CONDITIONAL <Shadow Name>"
then "commit"
> > causes any other in-process or out-of-process connection to be
> > until the shadow file is almost completely created. Testing
with a
> > 5Gb+ database. Shadow is over 4Gb+ in size before the other
> > connections are allowed to resume. I thought that shadow
> > would not block other users when it is being created. All of the
> > connections are using the same user "sysdba". Firebird is
running in
> > classic mode. OS is Windows XP-SP2 running on dual-Xeon 1.8s
with 2Gb
> > RAM. Plenty of HD space on SATA hard disk. I've tried
> > using multiple instances of IBExpert running as well as my
> > and all exhibit the same blocking mechanism. Has anyone seen
the same
> > thing and have been able to un-freeze this condition. Thanks in
> > advance for your assitance.
> >
> > Ron James.
> how often are you making shadows? I would have thought you create
it when
> you restore and that's it.
> Alan

Our system automatically backs-up and restores once a week. At that
point we need to re-create the shadow or have the restore create it.
One twist is that we have the system setup to do a complete fail
over to the secondary disk when a failure of the 1st disk is
detected and automatically activate the once shadow database into
the primary database. Our hopes were that the system would be
available for the users transactions as much as possible since the
users are concerned that the backup/restore weekly process can take
overnight on large databases. If Firebird blocks access to the
database while it creates much of the shadow, we will have to
potentially re-think the recovery strategy.