ORA-27121: unable to determine size of shared memory segment

If when you are trying to login to Oracle 10G on linux you get :

ORA-01034: ORACLE not available
ORA-27121: unable to determine size of shared memory segment
Linux Error: 13: Permission denied

This is caused by Oracle installer not setting setuid on $ORACLE_HOME/bin/oracle.
To fix do:

$ cd $ORACLE_HOME/bin
$ chmod 6751 oracle

via http://www.jasonash.com/techblog/index.php/linux/ora-27121-unable-to-determine-size-of-sh

Grid Control access to a Windows server

If you are trying to get Grid Control to access a Windows server and having trouble here’s a few things to check.

  1. Check that the host name credentials you are providing are the same as the user who install the database software on the Windows server.
  2. Check that the user is a member of the ora_dba local group on the server and
  3. Check that the Log on as a batch job local security privilege has been turned on.

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Creating a link between two SQL servers

To create a link between two SQL Servers you need to use the sp_addlinkedserver and sp_addlinkedsrvlogin stored procedures.


sp_addlinkedserver @server='DBLINK01',@srvproduct='',@provider='SQLOLEDB',@datasrc='SQL-HOU-01';

@server is the name of the link
@srvproduct is the type of product, by default SQL Server
@datasrc is the server you link to

Then, you need to set the username and password to use on the link.

sp_addlinkedsrvlogin 'DBLINK01','false',null,'sa','Pa$$w0rd';

The first parameter is the name of the link to use,
The fourth is the account of the remote server to use,
The fifth is the password for the account.