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Environment:
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4 x HIS 2000 servers
2 of the server are in 1 HIS subdomain (HISPROD) and the other 2 servers are in another HIS subdomain (HISCOLD)
The 2 set of servers has the same PU/LU configuration. The main purpose is to have the 2nd set to be on standby mode.
Servers were running on Token Ring connections, which talks to a switch, which then talks to mainframe. Each server has 3 token ring adapters, hence 3 connections to the switch.
Main objective is to migrate all 4 servers to ethernet connections and make sure they are functional in Ethernet environment.
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Planning:
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1. 2 of the servers are production servers. The other 2 are standby. Hence the plan is to get 2 standby servers into ethernet connection first, then migrate production users to connect to standby servers. Monitor connections for 2 weeks, then change productions servers to ethernet connections and migrate users back to production servers.
2. The migration will be using DNS repointing, meaning User querying for production servers' IP will be directed to Standby servers' IP
2. Migration need to be done 2 servers at the same time. This is due to the fact that they are both in 1 HIS subdomain. When HIS client is searching for a sponsor server, it will actually look at the sponsor server list setup on the client.
a. when it hits the first server, it will query for the LU that it is suppose to connect, if the LU resides in any HIS servers within the HIS subdomain, the client will be pointed to contact the HIS server directly.
b. If the LU is not in any HIS servers within the HIS subdomain, the client will refer back to the HIS client sponsor server list for the next server to connect.
** This is a key point why HIS servers within the same HIS subdomain needs to be migrated together. **
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Implementation
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1. Make sure both set of servers has the same SNA configurations. Export and import snacfg.
a. export sna configuration out. "snacfg /print > c:\snacfg.txt"
b. Modify snacfg.txt to fit the target servers configuration. (e.g. server name, remote host address ... )
c. Delete SNADLC settings (since the target servers already has that)
d. Delete server settings (since the target servers already has that)
e. Delete everything after the last workstation config (this includes printer, tnserver etc...)
f. copy the modified snacfg.txt to target server and import. "snacfg @snacfg.txt"
g. Normaly error will gives u the target line number, so just go back to the snacfg.txt to check
h. If there is no error, the import will be completed. Verify at SNA manager console.
2. Modify DNS to repoint servers.
a. identiy which zone DNS users are querying.
b. Change DNS settings to point to the new IP in each of the zone.
c. Wait for replication to complete to all your DNS servers. This will roughly be the AD convergence time if you're using AD integrated DNS. You can write a batch script to query all your DNS servers for the particular Host record. nslookup
d. Wait for IP cache on client's PC to update. This will by default be 1 hour.
3. Shutdown original 2 HIS servers and turn on the target 2 HIS servers.
4. Verify all PU connections are active.
5. Get user to verify.
