Re: Oracle 24x7 shops and Patches-Upgrades.
- From: Carel-Jan Engel <cjpengel.dbalert@xxxxxxxxx>
- To: niall.litchfield@xxxxxxxxx
- Date: Mon, 18 Dec 2006 21:00:15 +0100
One of my CT's sites has the perfect solution.
This is transaction clearing for POS terminals. They have a context
switch loadbalancing between two storage/server/db/application stacks.
Both are normally in service (in two locations 20M apart). One site can
serve all the load. If one site needs maintenance, the context switch is
simply pointed to the other site in stead of load balancing.
Both databases sync the transactions to each other, using Advanced
Replication (Asynchronous). Normally the backlog won't be more than 5-10
minutes, in extreme conditions 30 minutes. Losing one server implies a
worst case of losing half of half an hour of transactions. (Actually it
can be worse, when the other site is in maintenance at the loss). Half
an hour of transactions simply does not justify a huge RAC and whatever
full stack investment. If they lose the transactions they can easlily
survive that. And this works for some years alreay, so the ROI is
supporting the overall profitability nicely. No Data Guard, no RAC, just
(a lot of) common sense, no CYA, but knowledgeable thrustworthy
programmers/SA's/DBA's, no 'damagement', but entrepreneurs, that can
identify well skilled staff. (I should not that I got innvolved here
AFTER this thing was designed an implemented. No credits to me, I just
like the elegant solution a LOT).
Needless to say that the concept of designing an HA stack makes it all
much better maintainable, allows for real 24x7, rolling upgrades and so
on. Making som crippled stack HA afterwards is a challenge. You might
get close, but will hardly meet the requirements, and still spend a lot
of time, effor and money (blood sweat and tears).
Best regards,
Carel-Jan Engel
===
If you think education is expensive, try ignorance. (Derek Bok)
===
On Mon, 2006-12-18 at 19:02 +0000, Niall Litchfield wrote:
> Oh yes. I once asked a consultant "How long from when you arrived on
> site until you were allowed to bounce a 24/7 system?" It was measured
> in hours.
>
> On 12/18/06, Niall Litchfield <niall.litchfield@xxxxxxxxx> wrote:
> > On 12/16/06, Dhimant Patel <drp4kri@xxxxxxxxx> wrote:
> > >
> > > Hi Gurus,
> > >
> > >
> > > This seems very common issue but I am confronted with a requirement where
> > > we need to have 24x7 availability, no exceptions.
> > > There is no way we can have staging server (for patch testing before
> > > deploying on the production.) and we need to accommodate
> > > software upgrades without a planned downtime.
> >
> >
> > You *might* just possibly be able to upgrade your own in-house written
> > software without downtime. You *cannot* maintain Oracle software without
> > downtime - 11g promises the actual shipping of 'rolling upgrades' just about
> > 1/2 a decade after Larry first mentioned them. Until then (and it would be a
> > brave person who relied on that particular feature in it's first release)
> > then you cannot achieve 24*7 without either
> >
> > 1) redefining 24*7 to 100% availability within service hours. or possibly
> > 2) never upgrading any part of the system again.
> >
> > Both options 1 and 2 are perfectly acceptable and professional approaches of
> > course.
> >
> > I'm also wondering how shops having 24x7 availability addresses such issues?
> > >
> > > Since I'm focused solely on Oracle, I'm not aware if any database server
> > > allow patching/upgrading without bringing down the server?
> > > Is any mainstream database server offer such solution?
> > >
> > >
> > >
> > >
> > > Thanks,
> > > DP.
> > >
> >
> >
> >
> > --
> > Niall Litchfield
> > Oracle DBA
> > http://www.orawin.info
> >
> >
>
Other related posts:
