Compare databases main and standby

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Compare databases main and standby

Post by bot » 25 Apr 2012 11:14

Hi !!

Ok, this is my case:

I'm going to do 'bascul' on cpu main in a system with duplicated control (R9.0), but before that I want to compare the databases running both on cpu-a and cpu-b.
Documentation talks about 'checkdb', but it seems to me that this is a consistency check, not a comparation between cpu's databases.
I know about 'mastercopy', but what I'm looking for is something that tells me the differences between cpu-a and cpu-b, before 'bascul'.
Documentation mentions /var/log/iplink.log as a file where the system saves events about MAO changes , but I certainly don't fully understand it.

Any ideas ?
Thanks
Bot

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alex
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Re: Compare databases main and standby

Post by alex » 26 Apr 2012 07:41

bot wrote:I want to compare the databases running both on cpu-a and cpu-b.
There is no sense at all in comparing DBs on both CPUs.
1st of all, It is "hot standby" architecture - if it was properly put in service and run without any error then it means that both DBs are identical as Standby CPU can take over control at any moment.
2nd, imagine by using some tools you found some difference so what would you do next? Manually repair DB tables?
Right, you do "mastercopy". So if you are not sure about DB consistenciy just start with "mastercopy" - it would save you a lot of time.
If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.

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enio.eltz
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Re: Compare databases main and standby

Post by enio.eltz » 26 Apr 2012 09:39

Hi

Alex is right. There's no sense in check databases before doing mastercopy.
For example, you have CPU A main and CPU B standby. If you check manually the database, after a lot of time, you see there are differences, you must configure them to be A=B. Mastercopy does the job.
So that everything works rightly, CPU a and B must be equal, with the same database. So standby CPU can take control at any time.
Checkdb command does an integrity test, not a comparison between them.
Another thing, as I understand when you have duplicate CPU you have one IP address for CPU A, one IP address for CPU B and a third IP address for when CPU A or B is main. In this case you do the settings through this third IP address. The settings are done on both CPUs.

Regards.
Enio Eltz Filho
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Re: Compare databases main and standby

Post by bot » 26 Apr 2012 11:24

Thanks Alex.

I agree with you. To do 'mastercopy' is the answer when you see differences between databases.
But because of 'mastercopy' needs restart standby-cpu and stop telephony before run it (and don't forget Autostart in swinst), I was thinking of some check or command (before 'bascul') that was able to answer this question: Do I really need to do 'mastercopy' ?

Regards,
Bot.

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Re: Compare databases main and standby

Post by bot » 26 Apr 2012 11:42

Thanks enio.
For example, you have CPU A main and CPU B standby. If you check manually the database, after a lot of time, you see there are differences, you must configure them to be A=B.
Should it be any problem between CPU A and B conectivity after some time, is there any message or log in the system telling me : Ok guy, is time to "mastercopy'' ?.
as I understand when you have duplicate CPU you have one IP address for CPU A, one IP address for CPU B and a third IP address for when CPU A or B is main. In this case you do the settings through this third IP address. The settings are done on both CPUs.
Yes, I always do changes on Main Ip address.

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Bot.

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alex
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Re: Compare databases main and standby

Post by alex » 28 Apr 2012 02:21

bot wrote:I was thinking of some check or command (before 'bascul') that was able to answer this question: Do I really need to do 'mastercopy' ?
If there were no errors from Standby CPU after it was put in operation so there is no need for mastercopy - just do "bascul".
Actually with ACT architecture it is much easier - you have just a straight cable between two CPUs and this system's behaviour is 99,99% predictable - comparing to spatial redundancy where you have a lot of switches, routers, LAN administrators etc between CPUs.
If it looks like a duck, swims like a duck, and quacks like a duck, then it probably is a duck.

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Re: Compare databases main and standby

Post by bot » 28 Apr 2012 17:49

Ok Alex.
Thank you for your time.

Regards,
Bot.

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Eliott
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Re: Compare databases main and standby

Post by Eliott » 30 May 2012 02:12

I always do a mastercopy to hold both CPUs consistent.
I would prefer always the mastercopy way if I had the possibility to decide.
However there are different incidents showing you inconsistencies.
e.g. Incident 2686=MAO err on stand-by CPU but also incident 2014

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Re: Compare databases main and standby

Post by mohamed-eid » 31 May 2012 04:12

Hello All,

Also I have the same issue as Eliott mentioned.
and also I use the role main IP address for any configuration
e.g. Incident 2686=MAO err on stand-by CPU but also incident 2014

is it related with the connection between two CPUs?!, i.e. for crystal HW we have cables in the back panel of the PBX connecting the two CPUs, is there is any specification for theses cables.
Thanks and Best Regrads,
Mohamed Eid

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Eliott
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Re: Compare databases main and standby

Post by Eliott » 31 May 2012 07:22

Which CPU Type? CPU7 can communicate via IP.
Don't think the cables are the reason.
What's the system uptime?
Maybe the standby should be rebooted with mastercopy and all will be fine.

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