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Solaris OS Login is slow when DNS server is down

January 2, 2014

Solaris OS Login is slow when DNS server is down OR slow resolving when first nameserver is down.
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login as: root        ==> After entering Username it takes 10-15 secs
Using keyboard-interactive authentication.
Password:        ==> After entering Password it takes 10-15 secs

The above taking around 10-20 seconds to login, can be reduced to 2-3 secs by using options timeout:1,options attempts:2 as below:

ora12crac1:[root]$ uname -a
SunOS ora12crac1 5.10 Generic_147148-26 i86pc i386 i86pc

ora12crac1:[root]$ cat /etc/resolv.conf
domain mgdom.com
nameserver 192.168.56.99
search mgdom.com

Modified to :
=============
ora12crac1:[root]$ cat /etc/resolv.conf
domain mgdom.com
nameserver 192.168.56.99
search mgdom.com
options timeout:1
options attempts:2

http://unix.stackexchange.com/questions/78041/configuring-dns-resolver-failover-timeout

http://forum.directadmin.com/showthread.php?t=43981

options attempts:5

For Oracle check below note :

Top 5 Issues That Cause Troubles with Scan VIP and Listeners (Doc ID 1373350.1)

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Reduce the value for the lookup timeout so that the total lookup time is less than the check timeout for VIP resource

options timeout:1

Solution:
1) Have /etc/resolv.conf consistant across all nodes
2) reduce the value for the lookup timeout so that the total lookup time is less than the check timeout for VIP resource
– e.g.: add to /etc/resolv.conf: options timeout:1

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http://docs.oracle.com/cd/E11882_01/install.112/e24616/presolar.htm#CWSOL203
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When using GNS, you must configure resolve.conf on the nodes in the cluster (or the file on your system that provides resolution information) to contain name server entries that are resolvable to corporate DNS servers. The total timeout period configured—a combination of options attempts (retries) and options timeout (exponential backoff)—should be less than 30 seconds. For example, where xxx.xxx.xxx.42 and xxx.xxx.xxx.15 are valid name server addresses in your network, provide an entry similar to the following in /etc/resolv.conf:

options attempts: 2
options timeout: 1

search cluster01.example.com example.com
nameserver xxx.xxx.xxx.42
nameserver xxx.xxx.xxx.15

/etc/nsswitch.conf controls name service lookup order. In some system configurations, the Network Information System (NIS) can cause problems with Oracle SCAN address resolution. Oracle recommends that you place the nis entry at the end of the search list. For example:

/etc/nsswitch.conf
hosts:    files   dns   nis

From → OS, Unix

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