Forum Discussion

rcdauria

Level 4

10 years ago

Solved

Using Alternate Network with the new "Preferred Network" feature

Hi guys,

I have the following scenario:

-Windows Master Server
Hostname VTXMASTER01
IP 10.78.0.193 (Production Network)

-Windows Media Server
Hostname VTXMEDIA01
IP1 10.78.0.194 (Production Network)
IP2 66.66.66.66 (Backup Network)
IP3 67.67.67.67 (Another Backup Network I will need to use eventualy - not important right now)

-Windows 2008 Client
Hostname VTXFPS02
IP 1 10.78.0.24 (Production Network)
IP 2 66.66.66.67 (Backup Network)

Requisite is quite obvious: would like the backup to pass via the 66.66.66.0/24 network.Tricky part is: customer would not like to use hosts file solutions & etc, so I went down and took a look at the new Preferred Network settings (replaces the REQUIRED_INTERFACE and REQUIRED_NETWORK ones).

Very confusing guide, but undersood I could basically insert the 66.66.66.0/24 network as a MATCH in both media server and client, and everything would work (the specified network would be matched/used as the preferred path between the media server and the client). However, no luck: the entry was skipped and the backup went via Prodution Network. Looks like bptestnetconn does not know the 66.66.66.0/24 path:

bptestnetconn -f --prefnet -H vtxfps02

------------------------------------------------------------------------
NBU IP_ADDRESS_FAMILY configured to use Remote Addresses: IPv4(yes) IPv6(no)
FL: VTXFPS02 -> 10.78.0.24 : 0 ms SRC: ANY
------------------------------------------------------------------------

Tried changing the preferred network entry from MATCH to ONLY, but from this moment on the media server cannot connect to the client.

Any sugestions? I am using this feature the wrong way?

Thanks a lot in advance

Rafael

Windows Server (2003-2008)

Andrew_Madsen
10 years ago
It all begins with communication. If you want traffic to traverse the 66.66.66.0 segment you need to start it there. In order to start it there the master server needs to be able to talk to the segment and the various addresses need to resolve. It is not really DNS tricks, it is what DNS is supposed to do. It helps eliminate communication errors because someone failed to put in an entry into everyone's hosts file. Here is how it could look:

Master Server

VTXMASTER01 - 10.78.0.193 (Production Network)

VTXMASTER01-bkp1 - 66.66.66.68 (Backup Network 1)

VTXMASTER01-bkp2 - 67.67.67.68 (Backup Network 2)

Media Server

VTXMEDIA01 - 10.78.0.194 (Production Network)

VTXMEDIA01-bkp1 - 66.66.66.66 (Backup Network 1 )

VTXMEDIA01-bkp1 - 67.67.67.67 (Backup Network 2)

Windows 2008 Client

VTXFPS02 - 10.78.0.24 (Production Network)

VTXFPS02-bkp1 - 66.66.66.67 (Backup Network)

Your hosts file on the master would have entries for VTXFPS02-bkp1, VTXMEDIA01-bkp1, and VTXMEDIA01-bkp2. The media server would have entries for VTXMASTER01-bkp1, VTXMASTER01-bkp2, and VTXFPS02-bkp1. The client would have entries for VTXMASTER01-bkp1 and VTXMEDIA01-bkp1. Also there will need to be added the -bkp1 entries for the master and media in the client's registry for server access and in the master and media server.

Using a BAN (Backup Area Network) is a much better way of handling backup traffic and from your post the customer has certainly moved down the path to take advantage of it. All they need now is to finish it by adding the DNS entries and extra interfaces to the master server.

31 Replies

RamNagalla
Moderator
10 years ago
you might have verified it already..however just wanted to make sure before we check something else...

does the Media server is able to ping IP address 66.66.66.67, from its backup IP. its bit tricky to find in windows , however first confirm the normal LAN communication between the media and client over the backup network is fine .( i guees this is not the case)

when you do the ping from media server to IP 66.66.66.67, make sure it is using the IP of 66.66.66.66, and not the production IP first.
mph999
Level 6
10 years ago
On media server:

PREFERRED_NETWORK = <net add target>/<CIDR> MATCH <IP to go out on>

On client

PREFERRED_NETWORK = <net add target>/<CIDR> MATCH <IP to go out on>
rcdauria
Level 4
10 years ago
Hi guys,

Thanks for your replies.

Yes, then can ping each other normally.

@MPH999: thats exactly my setup (see below - media server 2nd IP address is actuall 66.66.66.69, not 66.66.66.67):

Rafael
mph999
Level 6
10 years ago
Hmm, what does bptestbpcd show, with the rule in place.
rcdauria
Level 4
10 years ago
Only production network IPs:

C:\Program Files\Veritas\NetBackup\bin\admincmd>bptestbpcd -client vtxfps02 -verbose
1 1 1
10.78.0.194:63973 -> 10.78.0.24:1556
10.78.0.194:63974 -> 10.78.0.24:1556
PEER_NAME = vtxmedia01.vantix.local
HOST_NAME = vtxfps02
CLIENT_NAME = vtxfps02
VERSION = 0x07610000
PLATFORM = win_x64
PATCH_VERSION = 7.6.1.0
SERVER_PATCH_VERSION = 7.6.1.0
MASTER_SERVER = azurenbumt01.vantix.local
EMM_SERVER = azurenbumt01.vantix.local
NB_MACHINE_TYPE = CLIENT
10.78.0.194:63975 -> 10.78.0.24:1556

C:\Program Files\Veritas\NetBackup\bin\admincmd>
rcdauria
Level 4
10 years ago
Actually I've been thinking: does the Preferred Network feature relates to all communications (including "control" traffic) or only backup stream.

Because if you think about it: how will the media server know the backup network IP of the client? It's not in the DNS, it's not inserted anythere in the configuration.

Only logic would be:

-Media connects into the client using production IP network
-Media obtains the list of available IP addresses
-Media "detects" there is a second path (the 66.66.66.0/24 network)
-Media decides, via preferred network rules, that the backup will come using this network.

But that assumes the control traffic would still work on the prodution (not a problem for me).

Howeber, if the rule specifies that EVERY traffic should go via the backup network, it would be like:

-Media tries to communicate with the client using the 66.66.66.0/24 network
-Media does not know the IP address of the client in this network
-Error

Makes sense?

The guide does not make it clear, very strange.
RamNagalla
Moderator
10 years ago
i understand that customer does not want to use hosts file tricks... however i would like to use it once for testing if the issue is only limited to the perfred network setting or somewhere else..

put below entry in media server host file

66.66.66.67 VTXFPS02

and below entry in client hosts file

66.66.66.66 VTXMEDIA01

and then see how it goes with bptestbpcd and regular backup,

if it works fine.. then issue is with perfered network setting.. and if it does not work that is the area you need to look for.
Andrew_Madsen
Level 6
10 years ago
In order to use the preferred network setting you need the Master server to be on the backup network as well. Also you need the client to be identified as the DNS name for the client's backup area network name in the policies and the media server as well as the master server need a DNS entry for the backup network. Otherwise the master server will initiate all traffic over the production network and that is where it will stay.
mph999
Level 6
10 years ago
I'm not sure if that is correct, certainly it's not my understanding ... If it is it is bad design ...

You may have media servers with unique backup networks to a set of clients that are complete separate from any backup network the master may be on.

However, I may well be wrong, I'll see what I can find out. One of the guys in the US is very knowledgeable on this feature, I'll try and get hold of him.
mph999
Level 6
10 years ago
This could be worth trying ...

PREFERRED_NETWORK = <target ip> MATCH <outbound ip>

... use bptestbpcd to check if it goes out on <outbund ip>

It's not ideal, as it is specific to each client - but it's about as simple as this option gets, so I just want to see if it has any effect.