HMC Tips VII - General Terms

1. What is the maximum number of servers managed by HMC ?

> Maximum of 48 non-590-595 servers
> Maximum of 32 590/595 servers

2. What is the maximum number of LPARs supported by a HMC ?

> Maximum of 254 LPARs

3. How many HMCs can manage a server at one time ?

> You can have a maximum of 2 HMCs manage a server at one time

4. What are the different types of dynamic operations you can do with CPU, Memory and I/O Adapter on a LPAR ?

> Add
> Remove
> Move

5. How do we connect the HMC to power machines ?

For Power-4 machines, we connect the hmc using serial cables.

But for Power-5 machines, HMC connects to service processors via SSL-encrypted Ethernet, replacing the serial cables.

6. Do we have firewall configured in HMC ?

Yes. Each network card has an integrated firewall.

7. Do we need to configure DHCP in HMC ?

HMC may or may not act as a DHCP server for entry and mid-range servers.

But for high-end servers like P595, HMC must be a DHCP server

8. Can we have the same HMC to manage P4 and P5 machines ?

POWER5 HMCs cannot manage POWER4 servers, and vice versa.

9. Can we have the existing P4 HMCs upgraded to support P5 machines ?

Yes. We can. This involves a complete overwirte of teh disk and the loss of all previous configuration including user profiles.

10. What to do incase of disk failure in HMC ?

We can restore the HMC using recovery CD.
Then restore the latest Critical consule data backup which will restore the profiles, user ids, passwords, etc..

11. What is the default user id and password for the HMC ?

When the HMC is powered on the first time, login as hscroot and password as 'abc123'.

12. Can we manage a power machine without a HMC ?

Yes. We can run a server in manufacturing default mode, will all resources but no logical partitionings, CoD or Service Focal point,etc.. For entry level server, we can use the Integrated Virtualization Manager.

13. What is the network critetia for dual HMC connection ?

Dual HMCs require two different private networks.

14. What is the default service processor IP address in Power-5 Machines ?

Eth0 - HMC1 - 192.168.2.147 / 255.255.255.0
Eth1 - HMC2 - 192.168.3.147 / 255.255.255.0

15. What is the default user id and password for accessing service processor ?

User id - admin
Password - admin

16. Do we need a HMC for p5 model servers ?

One HMC is mandatory for 590, 595 or 575.
Dual HMC are recommended.

17. Do we need private network for HMc connectivity for p5-595 ?

One private network is mandatory for p5 590,595 or 575.

18. Can we have IVM support multiple servers ?

One IVM allowed per server and it only manages partitions on one server.

19. What does FSP (Flexible Service Processor) has ?

FSP has
a. Operating System
b. UserIds / Passwords
c. Filesystem
d. Networking
e. Firewall
f. Webserver
g. ASMI
h. Firmware

20. What to do if you forgot the admin password for FSP ?

If you do not know the admin password, place a hardware call with IBM to get 'celogin'.

21. What to do if you forgot the HMC hostname/ipaddress for a long running LPAR ?

You can always get the HMC IPaddress from a LPAR if we have performed "handshake" with the HMC.

Issue the below command to get the HMC IPAddress

# lsrsrc IBM.ManagementServer
Resource Persistent Attributes for IBM.ManagementServer
resource 1:
Name = "169.121.54.48"
Hostname = "169.121.54.48"
ManagerType = "HMC"
LocalHostname = "169.121.54.59"
ClusterTM = "9078-160"
ClusterSNum = ""
ActivePeerDomain = ""
NodeNameList = {"SAP-PRodServer"}

22. One HMC should be within 8metres of Managed Server

23. Each FSP Ethernet port should be connected to only one HMC