SYNC TIME ON APPLICATION SERVERS AND DATABASE SERVERS

Question

Our case is:
We have system used for north america (NA) and system used for Europe (EUP).
North American users are using NA systems (say P510 system), Europe users are using EUP systems (say P710 system).The system time on NA systems are EDT, the system time on EUP systems are CEST
for exmaple:
NA systems:
[CA096658@st1lx014 ~]$ date
Tue Sep 29 20:45:31 EDT 2009
EUP systems:
[CA096658@st1lx008 ~]$ date
Wed Sep 30 02:29:28 CEST 2009
P510 is the production system for NA, there are 4 application servers, 2 database servers, RAC, the system time show up on the os on these 6 servers are not sync, we want to sync the system time on these 6 servers to be the same EDT time. same thing to EUP systems, we want to sync the system time to be the same CEST time.
We need to change that at the unix level, my question is:
1) do we need to change anything at the database and application level ?
2) before we change the time at the unix level, do we need to shutdown application and database ?

Answer 1

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1) do we need to change anything at the database and application level ?
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AFAIK, you do not have to change anything. EBS has the capability to perform timezone conversion. Pl see MOS Doc 330075.1 (User Preferred Time Zone Support Guidelines for Applications 11i10CU2)
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2) before we change the time at the unix level, do we need to shutdown application and database ?
>
It is best practice to shut down all applications/databases before changing server time.
HTH
Srini