> It would seem to me, based on reading past messages, that having an after
> image file would be almost a no brainer, assuming it isn't slowing the
> database down noticeably.
>
> Of course, if the after image file is on the same drive as vantage, and
> the vantage db is lost, there's a good chance the AI would be lost too.
> What if the AI file is stored on another server. Would that slow vantage
> down significantly? We are currently running our two servers with 2 load
> balanced 100mbps NIC's apiece. I'd probably consider storign the AI on
> our separate file server, which is running RAID 10.
>
> We probably wouldn't implement an AI file until we upgrade our vantage
> server, which is currently a 450mhz pII with 512 megs, running a mirrored
> pair of SCSI drives. We'll probably be upgrading to a vantage server with
> RAID 10, and implementing a Gigabit backbone.
>
> TIA,
>
> Thaddeus Jacobs
> Information Solutions Developer
> Kinematic Automation, Inc.
> mailto:tjacobs@...
>
>
> >a previous post from William E. Colls regarding AI files
>
> ai is after image.
>
> That is a log of completed transactions (in Progress's internal format -
> not something you can read). It has two principle uses:apply
> transactions after a restore from a back up, and as means of maintaining
> a "warm" backup in situations where very rapid restart after a crash is
> REALLY important.
>
> Generally, on a well tuned system the overhead is trivial. The benefits
> can be significant. After your db has crashed at 4:45 pm, and you have
> recovered the backup from last night (You do have a backup from last
> night, don't you?) which is easier: apply one or two ai files to add
> today's work exactly as it was done during the day - resources required
> 1 person for 15 minutes; or keep the whole office back for 4 hours to
> re-key all the days work, assuming everyone can remember exactly what
> they did and in what order - resources required you do the math.
>
> 'Nuff said.
>
> --
> /* ================================================================*/
>
> Specialists in Progress Databases and Software since 1986
>
> William E. Colls william@...
> PROComputer Systems Tel 613 591 0079
> 67 Willow Glen Dr. Fax 613 591 3924
> Kanata Ontario Canada www.procomsys.com
> K2M 1T1
>