Calling Acp Neeku Rac Interview Pedutunna..tondaraga Raa!

[PMREDDY19]

[quote name='Silence..Please' timestamp='1324400282' post='1301170785']
RAC valla andhari ki work untundi .. like Sys admin will have to do some work .. DBA's need to do some .. even application folks will have to do the configurational settings differently .. kani end-user ki internal ga em aina kuda.. antha transparent ga untundi .. andhu k clients wants to get into RAC
[/quote]

Hmm RAC lounna kaani , u are not making Datacentre failovver,, from a weblogic server point of view,

if any of all the 3 nodes inside a 3-node RAC is Running and not holding any requests from my server before it times out.. we are happy..

but if the whole Datacentre is down, in that situation, we are into a critical path of redirecting all the traffic form our current Data centre to a DAtacentre.. we consider that scenario as a Failover ..


But if all the requests are served by a single Datacentre with 3 servers clustered in a RAC., we are not bothered.


but now in our current project, we are implementingg somethin new,, with App server making connecitonss across Load balanced kind of datacenters Runnign on 4 differnt locations around the world.. ]

2 DB servers in US< 2 DB servers outside the USA<>
i

[Spartan]

[quote name='Silence..Please' timestamp='1324400910' post='1301170848']



pedha clients tho work chesetapudu .. e interaction pedha headache evariki vaallu safe-side undhaam ani chuusthuntaaru .. so yedhaina thappu jarigithe .. so n so person alaane configure cheyyamannaadu .. so we did it anesthaaru
[/quote]

vallu full timeers untaru...anduke safe side...etteste malli kashtamani.....

[k2s]

[quote name='PMR aka OM' timestamp='1324400956' post='1301170855']

Hmm RAC lounna kaani , u are not making Datacentre failovver,, from a weblogic server point of view,

if any of all the 3 nodes inside a 3-node RAC is Running and not holding any requests from my server before it times out.. we are happy..

but if the whole Datacentre is down, in that situation, we are into a critical path of redirecting all the traffic form our current Data centre to a DAtacentre.. we consider that scenario as a Failover ..


But if all the requests are served by a single Datacentre with 3 servers clustered in a RAC., we are not bothered.


but now in our current project, we are implementingg somethin new,, with App server making connecitonss across Load balanced kind of datacenters Runnign on 4 differnt locations around the world.. ]

2 DB servers in US< 2 DB servers outside the USA<>
i
[/quote]
Global Traffic Management

[Gachibowli_Diwakar]

[quote name='PMR aka OM' timestamp='1324400956' post='1301170855']

Hmm RAC lounna kaani , u are not making Datacentre failovver,, from a weblogic server point of view,

if any of all the 3 nodes inside a 3-node RAC is Running and not holding any requests from my server before it times out.. we are happy..

but if the whole Datacentre is down, in that situation, we are into a critical path of redirecting all the traffic form our current Data centre to a DAtacentre.. we consider that scenario as a Failover ..


But if all the requests are served by a single Datacentre with 3 servers clustered in a RAC., we are not bothered.


but now in our current project, we are implementingg somethin new,, with App server making connecitonss across Load balanced kind of datacenters Runnign on 4 differnt locations around the world.. ]

2 DB servers in US< 2 DB servers outside the USA<>
i
[/quote]
data centre fail aithe .. apudu ika disaster recovery ye ga

RAC cannot be configured across data centres .. because .. inter node communication ki giga bit ethernet cards use cheyyaali ..

[vijay2349]

[quote name='Silence..Please' timestamp='1324400599' post='1301170818']

as far as I know ... split brain syndrome will be handled by Oracle itself internally .. documentantion chadhavaali nenu kuda.. how exactly it works anedhi ... u dont have to do anything externally to side-track this issue

inka control file annaav .. ye control file ? if it is about db's control file .. adhi shared storage meedha untundi .. so it shudnt be effected

e article chadhvu . simple terms lo explain chesthadu

[url="http://apunhiran.blogspot.com/2009/04/what-is-voting-disk-split-brain.html"]http://apunhiran.blo...plit-brain.html[/url]
[/quote]

in a 4 node rac


node 1 and node 2 not able to communicate with node 4

but node 3 able to to communicate and node 1,2,3,in themselves also.

so now how split brain sysdrome works.

[PMREDDY19]

[quote name='k2s' timestamp='1324400612' post='1301170819']

affudu maa deggariki ostaru.. load balancers lo pools, VIPs , SNATs creat cheyyamani
[/quote]

idhigo ilaangey monna nite club ki poyi egirivachii,, chck cheyyaledhu implement chesaado ledho ani

ippudu naa saavuki

Load balancer meeda SSL veyyamani sepithey mee vaalu main vaadu leave lo unnadu ,., alternate vadu sariga pani cehyyaledhu ,, and I need to wait for this implementation until next weekend again//

[PMREDDY19]

[quote name='k2s' timestamp='1324401061' post='1301170865']
Global Traffic Management
[/quote]

yep ilantidhey baa..

Anni Solaris Dabbalu pedtunanru anukunta...

migilina RAC kosam emo HP DL 580.380 pedtunanru.. e global kosam emo
solaris T3-1 anukuntaa using.. not sure emi request pettaaro maa valllliu gurthu ledhu..

[k2s]

[quote name='PMR aka OM' timestamp='1324401126' post='1301170873']

idhigo ilaangey monna nite club ki poyi egirivachii,, chck cheyyaledhu implement chesaado ledho ani

ippudu naa saavuki

Load balancer meeda SSL veyyamani sepithey mee vaalu main vaadu leave lo unnadu ,., alternate vadu sariga pani cehyyaledhu ,, and I need to wait for this implementation until next weekend again//


[/quote]
wait seyyali oooy mari

[Gachibowli_Diwakar]

[quote name='AFDB SREERAAMUDU' timestamp='1324401124' post='1301170872']

in a 4 node rac


node 1 and node 2 not able to communicate with node 4

but node 3 able to to communicate and node 1,2,3,in themselves also.

so now how split brain sysdrome works.
[/quote]
naku antha deep ga teleedu ba .. how oracle exactly works ani .. kani voting disk usage ochedhi ilaanti cases lo ne anukunta

[k2s]

[quote name='PMR aka OM' timestamp='1324401214' post='1301170882']

yep ilantidhey baa..

Anni Solaris Dabbalu pedtunanru anukunta...

migilina RAC kosam emo HP DL 580.380 pedtunanru.. e global kosam emo
solaris T3-1 anukuntaa using.. not sure emi request pettaaro maa valllliu gurthu ledhu..
[/quote]



endo dabbala gola antava ?

[vijay2349]

[quote name='Silence..Please' timestamp='1324401296' post='1301170889']
naku antha deep ga teleedu ba .. how oracle exactly works ani .. kani voting disk usage ochedhi ilaanti cases lo ne anukunta
[/quote]

yes baa,kani nuvvu icchina doc link lo vaadu controlfile ani mention chesadu instead of voting disk anduke doubt vachhi post eesanu.

[k2s]

[quote name='AFDB SREERAAMUDU' timestamp='1324401124' post='1301170872']

in a 4 node rac


node 1 and node 2 not able to communicate with node 4

but node 3 able to to communicate and node 1,2,3,in themselves also.

so now how split brain sysdrome works.
[/quote]

[size=5][color=#000000][font=tahoma, verdana, sans-serif]It occurs when the instance members in a RAC fail to ping/connect to each other via this private interconnect, but the servers are all pysically up and running and the database instance on each of these servers is also running. These individual nodes are running fine and can conceptually accept user connections and work independently. So basically due to lack of commincation the instance thinks that the other instance that it is not able to connect is down and it needs to do something about the situation. The problem is if we leave these instance running, the sane block might get read, updated in these individual instances and there would be data integrity issue, as the blocks changed in one instance, will not be locked and could be over-written by another instance. Oracle has efficiently implemented check for the split brain syndrome.[/font][/color][/size]


[size=5][color=#000000][font=tahoma, verdana, sans-serif]In RAC if any node becomes inactive, or if other nodes are unable to ping/connect to a node in the RAC, then the node which first detects that one of the node is not accessible, it will evict that node from the RAC group. e.g. there are 4 nodes in a rac instance, and node 3 becomes unavailable, and node 1 tries to connect to node 3 and finds it not responding, then node 1 will evict node 3 out of the RAC groups and will leave only Node1, Node2 & Node4 in the RAC group to continue functioning.[/font][/color][/size]

[size=5][color=#000000][font=tahoma, verdana, sans-serif]The split brain concepts can become more complicated in large RAC setups. For example there are 10 RAC nodes in a cluster. And say 4 nodes are not able to communicate with the other 6. So there are 2 groups formed in this 10 node RAC cluster ( one group of 4 nodes and other of 6 nodes). Now the nodes will quickly try to affirm their membership by locking controlfile, then the node that lock the controlfile will try to check the votes of the other nodes. The group with the most number of active nodes gets the preference and the others are evicted. Moreover, I have seen this node eviction issue with only 1 node getting evicted and the rest function fine, so I cannot really testify that if thats how it work by experience, but this is the theory behind it.[/font][/color]
[color=#000000][font=tahoma, verdana, sans-serif]When we see that the node is evicted, usually oracle rac will reboot that node and try to do a cluster reconfiguration to include back the evicted node.[/font][/color][/size]

[size=5][color=#000000][font=tahoma, verdana, sans-serif]You will see oracle error: ORA-29740, when there is a node eviction in RAC. There are many reasons for a node eviction like heart beat not received by the controlfile, unable to communicate with the clusterware etc.[/font][/color][/size]
[color=#000000][font=tahoma, verdana, sans-serif][size=5] [/size][/font][/color]
[size=5][color=#000000][font=tahoma, verdana, sans-serif] [/font][/color][/size]

[PMREDDY19]

[quote name='k2s' timestamp='1324401266' post='1301170886']
wait seyyali oooy mari
[/quote]

first asalu Business vadu emo no SSL nothing annadu , maa Security vaadu emo no way u gonna server external customers with a user login page and no ssl annadu, aslu meeku evadu implement chestado chusukunnaamu ani kottadu..


so malli maa business vadu compromise ayyi edho chesadu alaa ala . set ayyindhi..

[Gachibowli_Diwakar]

[quote name='AFDB SREERAAMUDU' timestamp='1324401412' post='1301170899']

yes baa,kani nuvvu icchina doc link lo vaadu controlfile ani mention chesadu instead of voting disk anduke doubt vachhi post eesanu.
[/quote]

aah doc id yedho ichadu ga .. adhi chuusi clarify chestha le .. nee doubt

[PMREDDY19]

[quote name='k2s' timestamp='1324401307' post='1301170891']



endo dabbala gola antava ?
[/quote]

Eggss Actly , hapy ga oka weblogic package, 4 extract, create commands kottukuntu,, rendu cron jobs perlu chepppu root access teesukuni gadipesey vadini aa rojullo

ento ikakda e RAC antadu , Solaris antadu , VMA ntadu , okkati ardam ayyi saavadhu ,

,mallli Edho blade antadu , VMs powered down antadu , console acces anntadu ,KVM serial access antadu..


DNS request, firewall request, hardware monitoring request,, Load balancer request..






nenu kuda next inka Architect aipothaa,, Project plan DB lo post vesi.. discuss chesi appudu suggest chestaa business ki..