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Sunday, 5 August 2012

NetBackup 101! (Networks, hostnames, peernames and the kitcken sink)

People get confused about NetBackup 101's. I've extracted the following from some docs that I think are really useful getting back to the root. Hope it helps all those BAU people out there. Happy days.

Backups:

1) NBU connects to host name configured in policy (configured name)
2) OS on host resolves the name (Local or DNS/NIS)
3) Connection sent across network path defined by routing table
4) bp.conf on host is not a factor

5) When 'server' gets connection from client, server determines clients configured name from peer-name of its connection to server:

- peer-name is determined by ip address of the connection; i.e. the address must translate into a host-name (gethostbyaddr routine).

* bprd log entry * =
'connection from host peername ipaddress'

6) The clients 'configured' name is then derived from the peername by asking bpdbm (UNIX) or NBU DataBase Manager on Windows:

- bpdbm compares peername to a list of client names from:

a) All clients who've done a backup by using a simple string verification comparison by comparing hostnames&aliases (gethostbyname routing)

If not successfull then:

b) All clients in all policies by doing a brute force method.

7) The configured name is 1st comparison that succeeds

- other comparisons might have succeeded if aliases or 'network-names' (Local/DNS/NIS,etc) are configured.

8) If comparisons fail then client's hostname as returned by gethostname function on client is used as configured name
* bpdbm log with VERBOSE gives you information *

- you can use bpclntcmd -pn on client to determine clients configured name, where:

a) 1st line is directed to server to which request is directed, (i.e. expecting response from server <servername> ) then,
b) 2nd line is servers response containing:
- peername of connection to the server
- configured name of the client
- ip address of the connection to the server
- port no. used in the connection

9) If gethostname or gethostbyname on client returns host names that are not qualified so that DNS on Master/Server cant resolve them, problems:
a) possible to configure local hosts on Servers/Clients
b) possible to use /usr/openv/netbackup/db/altname/host.xlate (UNIX) to create this file containing:

key hostname_from_client client_as_known_by_server

Where:
key = 0 ; must always be zero indicating a configured name translation
hostname_from_client ; must correpond to the name that is obtained by clients gethostname  and sent to the server
client_as_known_by_server ; is name to substitute for hostname_from_client. Must be the configured name in NBU conf on Master+must be known to Masters network service

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