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What is the role of Master and Media Servers

Hi,

 

I was wondering about this for some time. Beside the ability of Media server in different VLAN and managing the configurations from the master server, are there any other differences between Master and media servers.

 

Just pondering about this.


Thanks in advance!

 

 

11 Replies

Re: What is the role of Master and Media Servers

Basically the code is exactly the same, they just do different roles. The relationship is a many to one.  One Master, many Media Servers.  A media server, is simply a client that has tape drives assigned to it directly. So it can back itself up, or other clients. Then they send the metadata(catalog info) to the master.  Every NBU environment requires one Master, but you dont have to have Media Servers. If the Master has tape drives assigned to it, then it essentially behaves as both, accepting backup jobs, as well as tracking the metadata and catalogs.

Re: What is the role of Master and Media Servers

For big environment media server are used to load balance the backups, this way you dont have everything running through one box and also not all your drives are under a single media, for small environments with master-media is enough

Re: What is the role of Master and Media Servers

Thanks all for your input.

 

I have a medium size env (~150 servers), hence I don't envisioned the roles of media servers very much. With your explanation I kinda understand the needs much better.


Thanks a million! 

Re: What is the role of Master and Media Servers


I am not a netbackup expert here but I think the need for one or many media server will depend on a few questions :
 
1. How much data do you backup in one night....(weekly full, monthly full, cumulative incremental) ?
2. How many tape drives do you have ?
3. What is the speed of the tape drives, are the tape drives writing as fast as they can or can you get better/faster performance out of them ?
4. How are the servers connected to each other....(10 MB, 100 MB, 1 GB, Fiber, ISCSI)?
5. How large is your backup window, do you want to shrink the backup window ?
6. Do you perform encryption or compression...if so why not spread the overhead on multiple media servers ?
 
Compared to your medium size environment (~150 servers) ....I have only about 30 servers.
 
I backup about 80 GB on a cumulative incremental and about 1.4 TB on a full.
My cumulative incremental takes me about 2 hours and my full takes me about 12 hours with a lot of white time in between when no jobs are running and tape drives are free....this is with a high level of encryption. My environment can handle a lot more data within the backup window my company has set for itself.
 
I have one master server and 4 media servers. The master server does not write anything to tape so only 4 media servers are performing the tape writes.
 
I am not sure if I understood your response correctly .....so I apologize...but I really do think that depending on the answers to the questions above you could benefit from a few media servers.

Re: What is the role of Master and Media Servers

I guess I am confused also as to why having media servers would be beneficial.  We currently have 4 master servers, 1 at each campus, each with their own tape library attached.  We have about 150 servers to back up.  The reason we chose multiple master servers is that our retention policy is to keep a monthly backup of each server indefinitely, and all backups for 90 days.  Consequently, our catalogs can grow rather large, and just having one catalog seems like it would be too large to manage.

 

What would the benefit be to having media servers over multiple master servers?

Re: What is the role of Master and Media Servers

Ahhh...  150 clients spread across 4 sites.   I, like others, assumed you had 150 clients at one site and no media servers.  Sounds like you don't need them at all  :)

Re: What is the role of Master and Media Servers

Denise,

 

Multiple master servers might not be the wrong solution and the answer really depends on how each individual wants to manage their environment. For example...if the four campus locations are very far from each other and there will never be any sharing of media or writing to tape drives at different campus locations then one can easily manage this by having four different master servers...as in your setup. Or, one might choose to have one master server and 3 media servers where the master will be the 4th media server. This way you have one centeral location to perform all netbackup management tasks except for tape insertion and ejection and thus you only manage one database. In this second scenario Media Server A will write locally to its tape drive all of the servers in its location and Media Server B will write all its local servers to its attached tape drive..etc.

 

I imagine cost for master server with all options versus the cost of a media server has got to be different.

Plus just the pure management of multiple master servers could be cumbersome.

 

Finally, you could choose to purge your NBU database as things age. The only drawback would be if you ever wanted to restore from an old tape you would have to restore the database first. 

 

 

Re: What is the role of Master and Media Servers

Actually, I am a different member than the person who opened this discussion, I have wondered about the roles of masters and media servers myself, so I was reading this thread and chimed in with my story. 

 

So, if the servers are split up to different campuses, there is no need or advantage to using media servers?

Re: What is the role of Master and Media Servers

It all depends on your WAN links, budget, and whether you want centralised control, or disparate systems.

 

I think you're better off with 4 separate systems.  You could have one master/media, and three medias, and one big catalog - but if the master goes down - then you'll have no backups and no restores at any site.  At least with 4 separate systems, they're not reliant on each other.

 

On the downside, if you want to migrate backup data from one site to another, or restore the data from client A at site A onto client B at site B, then you have physically transport media and site B's master server has to import site A's media before you can restore.  But I should think that this doesn't happen very often.  A centralised system with media servers might not necessarily help in this situation either if you WAN links have limited bandwidth, then any cross site restores could run for days and actually end up being slower and more flakey.

 

The meta-data coming back from media servers to populate the master catalog isn't that heavy, but it's still traffic and you would need the links up 24x7.

Re: What is the role of Master and Media Servers

OK, thank you.   I am thinking I like the 4 master server configuration.  I would hate to lost ALL backups if the only master server I had failed.

Re: What is the role of Master and Media Servers

Denise,

 

Just a point of clarity...you won't loose your backups if the master server fails. All you loose is the database which telly you which server was backed up when and to which media. The physical data written to tape is still on tape. As for the master server all you would need to do is restore your most recent catalog backup and you are back in operation.