IP Fail Over-Back Prog's

[Amit]

Hi, 

	IP changeover program does not need to generate traffic to check
weather the primary server is up or not. We can check network(with
packet sniffer) to find weather something is going on between clients
and server. Accordingly failover can occur. So I guess we won't need
any private circuit between two servers and ours aim is to get Clients
reach the Server and not that the primary and secondary talking. I
coded something and my plan is like: Please do tell me for any
drawback/loop in block diagram. I look forward to some sugessions!

1. It Should be Practical
2. Fool proof. & stable
3. Should NOT be resource hungry.
4. Flexible/precise & Easy to install/configure
5. Should have more options like manual & scheduled failover.

	Working: My Personal thinking

Check Weather Master IP is in use by directly connecting to some port
on that IP.
 |
 |- No ----Become Primary
 |
 |-Yes--Are you configured to be primary
         |
         |--Yes--contact secondary & Schedule for nearest even
time(30Sec to 1-5min.)for failback and be primary
         |
         |--No--Run sniffer and check(30sec to 5 min) for network load
                 |
                 |
              No load--Create load and check for success
                         |
                         |--Yes--OKOK, return
                         |
                         |--No--Retry--and next time FailOver.
                          

Primary: a) Create alias to get server up.
	 b) Take control of disk.
	 c) Fork Sniffer Application and run command/scripts as req.

	Yesterday I tried to change number of shared HDD from sda to sdb. I
changed the SCSI card Slot from 1->6(last). but it didn't worked. I
also consulted the manuals. Though at bootup First embedded HDD is
shown and BIOS installed but While booting Linux(even NT) sda(Disk0)
is assigned to Shared HDD only. Anyway I believe this is definitely a
hardware configuration problem and limited only to this kind of
server(Digital Prioris Hx6000). Also regarding Disk - Please tell me
someways to remove identity of shared disk from secondary server.


Thanks

Amit Gupta.


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