Physical standby database and we’re going to creep on here and I’ll do before Colonel working with the truth workmen’s already we can do this bit more quickly than we would normally be much but let me know if it’s like some more sign anything but clearly, we know what a physical some naive will run to basic check for the environment and then you all work or ask just going to put this into the chat wasn’t I my multi cannons in there we go that’s multi-tenant in 29 now so Oracle met the more love anything else problems I’ve had with data guard have hasn’t caused by issues with sequel net that’s what’s caused the problems it’s been issues with sequels it’s caused the issues more than anything else so the mange going to stick like that and perhaps slightly greater detail than you would normally, of course, you’re all right people now so you’ll be you’ll know more about sequel net than minus ten DJ’s if anything so we need to be sure we’ve got sequel left configured correctly.
There are several options here I’ll show you how we do it now all sentenced I’ll show you how I do it and if any of your life systems got to be sufficiently you can certainly see kind of stand there as well now configure sequel right then this repair she works given on the primary instance and delicious and I already said before the break we are going to be really precise our terminology instance the instance memory structures and processes the database files on disk alright we’re going to be professional terminology the instance of elevation and then will perish you out there and will create the samba instance and somebody’s herbaceous and then see it’s actually working that’s your basic physical standby done now the physical standby bond-buying for bite identical now that doesn’t mean of course it has to be pasta be identical I already mentioned we could have Linux and windows into operating.
So clearly the file name is a difference in the power of difference but as far as Oracle’s concerns the block structuring is a byte for byte identical headline usage 0 dash horse so how do you instantiate it for a backup or copy of the primary terminology here I’m in the world oil man with this point you can create it in a backup set or from image copies well the way because of doing it they’re the best snapshot that’s one way or another it’s basically a backup or copy of the primary donation and then we have three do apply the big contrast here is Right apply of against sequel apply sequel apply is the term we use strings or logical standby so really you apply change vectors and if we could decode the contents of the redo log which some people manage to do we’d see this change make sure is a physical address so update these bikes from this value to that value nothing logical about this all what transactionally aware is just change vectors applies.
The physical level open read-only that came in from Shi and of course Patrick data guard it can be opened read-only while applying three do, so that’s what our physical standby is and its protection against their loss now what does it protect you against damage too far off you mentally aware of what the physical standby when you’re actually going to do this and physical standby you don’t fail over very often I hope how many of you failed over recently when did you last failover DR test yes just for testing nothing interesting this, yeah you spend all this time and money getting media systems available in other user and that’s why I like their facilities but get the real value after these things I’ll take backups to the width of time until you need it absolutely it is very difficult to load to position this correctly the first Noreen I data God Chester I ever set up there’s when I still lived in South Africa as many years of silver and we were setting up that the first line.
I put them to a real there the guard ever set up, and this company called business connection there longer exists so I can name them and then won the contract with Man’s I’m sure we’ll know Man’s every big organization and business connection won the contract to run the demons global call centers and demons had call centers Oh is full of the son of three or fours and boss around the world huge call sign just as image and business connection run the copper won the contract to run my third base for them and one of the conditions demons put on them was that they have to have a physical phone line place because 24-hour operation zero-days worse and worse and the guy a business connection running that contracts he was basically a bit of an idiot in quite a few ways and teams and I was just got subcontractors help set up the standby and he’s coming up in these stupid comments as I’ve just had to spend two hundred thousand dollars on this sun PARC server.
Now it’s just sitting there doing nothing isn’t that stupid and I tried to explain to him yeah that the reason that thing was there sitting doing nothing yeah that was his job yeah it was doing quite a lot fewer people don’t found us and it can be difficult to say go to have all these PR sites available which you never use until this Chris says until you need them and then you find you haven’t so bad line usage if physical damage but you very rarely failover, if your database consists of say 500 files and one of them gets damaged it’s something, goes wrong with the file are you going to failover to the standby because of that probably not if the damaged files part of system or I should Matthew your database consists of five hundred data files Oracle uses the term practical file to refer the files that will cause the instruments to fail so you’ve got 500 data files you’ve got your control file.
You have got your online mod files which in these are the critical files it will cause in Central someone blows away the control file debt would think of a shawl follow is critical and terminology some people say you have one control file several copies of people say you have several control files plural I talked about one control file type or copy just so you know when I say the control file I mean all copies of it and it’s any copy of the control file goodbye database what’s other files are critical files universe and you can know it depends on how they’re striped you can live without I knew you can live without temp it will crash immediately because you can recreate it you can live without undoing any writer that sent can be more critical undo is 0 unless you’ll think of a rack oh yeah well undo cause one instance to go okay an institution the other one disabled search would actually say my life yeah undo Wisconsin is critical you can live without critical.
Its system this arc system is critical Seahawks you Rob your SOX is an idea well done without there eventually I’ll redo redo redo look if mas configuration assess at least one in at least one of each group yeah and always wondered about that why oracle will let you continue to operate the database we’ve damage to multiplex members of the redo log but will not let you operate the database we’ve damage to multiplex members of the copies of the control file always wondered why they made that decision, but that’s just the way.