cancel
Showing results for 
Search instead for 
Did you mean: 
Highlighted

Netbackup multiple NICs - Use Specified Network

Hi all,

Just would like to hear some of your opinions on the below scenario :

We have a Netbackup 7.1 / Windows 2008 environment for all master, media and clients. All servers (media + master + clients) have 2 NICs, one connected to the production network, and one connected to the backup network (different subnet). In the beginning, when the environment was set up, for some reason the admins configured all servers and clients to use the prod network interface. So alll clients and servers are having PROD hostnames.

Now, a few years down the line, they wanted me to change the clients to back up using the backup NIC. The problems are :

1) Backup network IP and hostnames are not in the DNS (due to some issue with firewalls and conflicts) - so if we need to use the backup NICs, all hostname mappings need to be maintained via the hosts file.

2) Netbackup master servers are clustered (Windows cluster) and the resource was using the PROD network IP, and because of the work that may be involved to change this resource to use the backup IP, we need to let it continue using the PROD network IP.

 

Now, my questions are :

 

1) I've been doing testing, by adding only the list of clients' backup IP addresses and hostnames to the master and media servers hosts files. For example, serverA is now serverA-NBU and serverA-NBU is defined in the master and media's hosts files.  I performed no changes on the client side (Netbackup client is still configured with its PROD hostname and IP). Then, I created a policy and added serverA-NBU. Without any other changes, I ran the backup. I noticed that, at first backup failed with 'client hostname not found' error, but miraculously, after 15 mins or so, I re-run the backup and this time it worked! I cant figure out why, l figured perhaps there was an update doing on or some sort. While I re-ran the backup, I turned on Network Monitor on the client side and started tracing both the PROD and the Backup NICs. What I found was that, the pbx traffic was happening on the Backup NIC (between the client and the media server), which is good, however I still see that the bpfis traffic was happening on the PROD NIC. So I am wondering - is my backup traffic actually going through the PROD interface, or Backup interface?

 

2) In my scenario above, since backup using the clients backup interface seems to work just by using the client's backup IP/hostname without any further changes - do I still need to configure the following :

a. Use Specified Network Interface setting on the client properties - so far I did not do this and backup worked.

b. Preferred Network - I did not configure this.

c. Adding the Backup NIC IP address for the master/media servers to the list of servers configuration on the client side - so far I did not do this but backup still happened successfully. I saw in the client's bpcd log that it saw oncoming traffic from MediaServerA (but this traffic came from MediaServerA's backup IP), so it did not deny it because the hostname matches the one in the serverlist. I am surprised at this because I thought the client would not be able to resolve the MediaServerA's backup IP at all because I did not add any mappings in the clients hosts file! So I am a bit confused.....

 

In a nutshell, I guess I just want confirmation, what configuration exactly is needed if I want to make sure that backup traffic is using the backup interfaces without having to actually change anything on the client side configuration (we have hundreds of clients and this would mean a lot of work). I  see from my testing that it actually worked (to an extent), but I'm not sure if what I'm doing is correct. We do not perform restore or backup from the client side (we do this only from the master server's administration console) so I thought maybe Use Specified Network Interface is not necessary.

Please correct me if I'm wrong and let me know your thoughts...

 

Thanks experts Smiley Happy you guys have been ever so helpful everytime I post something here, so kudos to all!

1 Solution

Accepted Solutions
Highlighted
Accepted Solution!

You have done an excellent

You have done an excellent job explaining your scenario and all the tests you've done so far.

One thing that is REALLY confusing when one introduces these changes is the mixed and very confusing results. This is because NBU uses host cache. So, whatever changes you make to hosts files and SERVER entries is simply ignored initially bacause NBU relies on its host cache.

What you need to do is to clear host cache after making changes. Even on the clients. I have had a situation where I tried to force certain errors for by changing IP addresses in my hosts file and then back my laptop up as client. I was surprised to see the backup still working. After clearing host cache I got the error that I expected.

bpclntcmd -clear_host_cache

Your logic and methods are good. It is just the host_cache 'playing games' with you!  You will have to add SERVER entries on the clients if you have 'NBU-IP    media-NBU' in the client's hosts file.

As you can see, there is no need for Specific Network or Preferred Network if correct naming convension is used right through.

There is a section in Chapter 2 of the Troubleshooting Guide under the topic "Verifying host name and service entries in NetBackup" (it should've been SERVER entries!).  Look for the 'clients in multiple networks' and 'servers in multiple networks' sections. The logic is the same for Unix and Windows.

Host cache TN: http://www.symantec.com/docs/TECH136792

Multiple NICs: http://www.symantec.com/docs/TECH54733

http://www.symantec.com/docs/TECH171040

View solution in original post

5 Replies
Highlighted
Accepted Solution!

You have done an excellent

You have done an excellent job explaining your scenario and all the tests you've done so far.

One thing that is REALLY confusing when one introduces these changes is the mixed and very confusing results. This is because NBU uses host cache. So, whatever changes you make to hosts files and SERVER entries is simply ignored initially bacause NBU relies on its host cache.

What you need to do is to clear host cache after making changes. Even on the clients. I have had a situation where I tried to force certain errors for by changing IP addresses in my hosts file and then back my laptop up as client. I was surprised to see the backup still working. After clearing host cache I got the error that I expected.

bpclntcmd -clear_host_cache

Your logic and methods are good. It is just the host_cache 'playing games' with you!  You will have to add SERVER entries on the clients if you have 'NBU-IP    media-NBU' in the client's hosts file.

As you can see, there is no need for Specific Network or Preferred Network if correct naming convension is used right through.

There is a section in Chapter 2 of the Troubleshooting Guide under the topic "Verifying host name and service entries in NetBackup" (it should've been SERVER entries!).  Look for the 'clients in multiple networks' and 'servers in multiple networks' sections. The logic is the same for Unix and Windows.

Host cache TN: http://www.symantec.com/docs/TECH136792

Multiple NICs: http://www.symantec.com/docs/TECH54733

http://www.symantec.com/docs/TECH171040

View solution in original post

Highlighted

Nightmare

I will recomend to rush in to a dns infrastructure, hosts files will give you a realy hard time, but u can create the hosts file and push it either with scp or bprestore.
Highlighted

Marianne, You are a genius!

Marianne,

You are a genius! Thats such a handy command, to clear host cache. Mystery solved Smiley Happy

The technotes help a lot as well - I've removed all unnecessary PROD interface hostnames from server list and backups go nicely now.

There's one thing I notice though - if I go now in the NBU administration console and try to access a client's Host Properties (using its backup interface hostname, for example, client-NBU), it will always fail with a "Ping failed on host client-NBU" error. But, if I access the client using its PROD interface hostname (for example, client-PROD), I can connect and access the Host Properties just fine.

This is a bit weird to me, because I'm able to backup successfully so obviously connection is not the issue. I think starting from 6.5, ping test is disabled when you try to establish connection with a server via the GUI, but it looks like its still doing it and failing, making me unable to access the Host Properties of the client. I guess, as a workaaround, I can keep both 2 version of the client in Netbackup (client-PROD and client-NBU) and access the client-PROD host properties if I need to change anything on the client side, but I am just wondering if this is normal behaviour or if there's anything I can change to make the Host Properties accessible via the client-NBU host interface.

 

Omar,

I agree with you but unfortunately the DNS situation wont change anytime soon..

I'm curious of the use of bprestore to "push" the hostfiles - is it possible to use bprestore to restore to multiple clients at the same time? I think I get the ideas that I may be able to restore the correct hosts file of Client B, to a CLient C,D, and E but I dont know whether this is possible. Your feedback is appreciated!
 

Posie

Highlighted

Is anything logged in

Is anything logged in Client's bpcd log at the time of the failed connection attempt?
If so, which IP address from Master is logged?

Bear in mind that during a backup connection is done like this:
master > media server > client

Host Properties is just doing:
master > client

Does 'bptestbpcd -client <client-nbu> -debug -verbose' work from master?

Highlighted
Moved:

Re: You have done an excellent