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Common NetBackup servers for duplication

CadenL
Level 6
Partner    VIP    Accredited Certified

Hi

I'm just trying to get to grips with the config I need to allow the following for a NetBackup 8.1.2 environment that is split across 2 sites. Site A has the master server and 1 media server and site B has two media servers - all servers are running NBU 8.1.2.

Media server 1 (on Site A) does a backup of a local client to a Data Domain storage server which then duplicates the backup image to another DD appliance attached to Media server 2 on site B. I next want to duplicate the image on media server 2 (Site B) to a locally attached tape device media server 3 (also on site B).

I have an SLP configured for the backup to the DD on Site A using storage unit configured on Media Server 1 as the backup destination. Under the properties of this storage unit I can see that media server 1 and media server 2 both have access to this storage unit but only media server 1 is ticked - media server 2 remains unchecked. My backup always uses media server 1 for the initial backup (happy days). The next stage of the SLP duplicates this backup image to Site B ontp Media server 2 using a storage unit configured on media server 2 for a second DD appliance on site 2. Under the properties of this storage unit I can see that media server 1, media server 2 and media server 3 all have access to this storage unit but only media server 2 is ticked - media server 1 and 3 remain unchecked. My duplication job always uses media server 2 (again, happy days).

The third stage of the SLP is the duplication to tape job. The tape drive is only attached to media server 3 and I have a media manager storage unit with media server 3 as the designated media server configured. When the third stage of the SLP runs it completes successfully but the media server isn't showing as media server 3 - it typically shows as either media server 1 or 2. What do I need to do to make media server 3 the 'common' media server for this stage? Will NBU always use a common media server by default these days?

I've seen it use media server 1 (on site A) for this stage and yet this media server is 'unchecked' in the properties of the storage unit - so how can it use it?

If I check the box to allow media server 3 access to the storage server used in stage 2 of the SLP will media server 3 then be considered as the common media server? But then will it also be used by media server 1 for it's duplication job to media server 2 (stage 2 of the SLP) as I only want media server 2 to be used for this bit.

thanks

 

1 ACCEPTED SOLUTION

Accepted Solutions

RLeon
Level 6
   VIP   

First, make sure the 3rd-stage SLP (with the Server3-attached tape storage unit) is further indented away from the 2nd-stage, so that it would definately duplicate from the 2nd-stage copy (Server2's DD), and not from the 1st-stage source copy (SiteA Server1's DD).
Then, in the 3rd-stage SLP, for the "Alternate Read Host" setting, set it to Server3, then try the job again.
Example:
Backup-to-Server1-DD
|__Dup-to-Server2-DD
      |__Dup-to-Server3-Tape-AltReadHost-Server3 (See how this is further indented away from the previous level)

If the 3rd-stage dup-to-tape jobs still give errors saying something about Server3 not having credentials to Server2's DD copy, then check Server2's DD's Storage Server properties (not Storage Unit properties) and make sure Server3 has access to Server2's DD copy. Then try the job again.

Explanation:
The "Alternate Read Host" setting in a duplication-stage SLP forces who gets to read the source copy during that stage. Leaving this blank will cause the stage to select a random Media Server that ALSO has access to the source copy***, to read the copy then pass it over the network (gasp!) to the stage's Storage Unit owner, to then write to the - well, Storage Unit it owns.

***But wait! (I hear you ask) Doesn't this mean that the SLP stage is ignoring the intentation that is telling it to ONLY use Server2's DD copy?
Well, yes and no. First, SOMEONE will definately read from Server2's DD copy to pass to the next stage, in accordance to the stage intentation you configured.
But, unless you configure the "Alternate Read Host", anyone with access to Server2's DD copy may randomly be picked to read it and pass it to the next stage******. NetBackup is weird like that.

******But wait! (I hear you ask, again.) In Server2's Stoage Unit, only Server2 is ticked, so only Server2 should be able to read it.
Well, no, actually. The "tick" in a Storage Unit only forces who gets to WRITE to that specific Storage Unit.
As for READ, that's another setting inside the DD's Storage Server properties. Currently, it seems Server1 also has READ access to Server2's DD, which explains why Server1 is sometimes randomly picked to READ from Server2's DD, then pass the data over the network (gasp!!) to Server3.

View solution in original post

2 REPLIES 2

RLeon
Level 6
   VIP   

First, make sure the 3rd-stage SLP (with the Server3-attached tape storage unit) is further indented away from the 2nd-stage, so that it would definately duplicate from the 2nd-stage copy (Server2's DD), and not from the 1st-stage source copy (SiteA Server1's DD).
Then, in the 3rd-stage SLP, for the "Alternate Read Host" setting, set it to Server3, then try the job again.
Example:
Backup-to-Server1-DD
|__Dup-to-Server2-DD
      |__Dup-to-Server3-Tape-AltReadHost-Server3 (See how this is further indented away from the previous level)

If the 3rd-stage dup-to-tape jobs still give errors saying something about Server3 not having credentials to Server2's DD copy, then check Server2's DD's Storage Server properties (not Storage Unit properties) and make sure Server3 has access to Server2's DD copy. Then try the job again.

Explanation:
The "Alternate Read Host" setting in a duplication-stage SLP forces who gets to read the source copy during that stage. Leaving this blank will cause the stage to select a random Media Server that ALSO has access to the source copy***, to read the copy then pass it over the network (gasp!) to the stage's Storage Unit owner, to then write to the - well, Storage Unit it owns.

***But wait! (I hear you ask) Doesn't this mean that the SLP stage is ignoring the intentation that is telling it to ONLY use Server2's DD copy?
Well, yes and no. First, SOMEONE will definately read from Server2's DD copy to pass to the next stage, in accordance to the stage intentation you configured.
But, unless you configure the "Alternate Read Host", anyone with access to Server2's DD copy may randomly be picked to read it and pass it to the next stage******. NetBackup is weird like that.

******But wait! (I hear you ask, again.) In Server2's Stoage Unit, only Server2 is ticked, so only Server2 should be able to read it.
Well, no, actually. The "tick" in a Storage Unit only forces who gets to WRITE to that specific Storage Unit.
As for READ, that's another setting inside the DD's Storage Server properties. Currently, it seems Server1 also has READ access to Server2's DD, which explains why Server1 is sometimes randomly picked to READ from Server2's DD, then pass the data over the network (gasp!!) to Server3.

View solution in original post

CadenL
Level 6
Partner    VIP    Accredited Certified

Hi

Firstly - great post and many thanks for taking the time to explain things so well.

Simply put, I just needed to set the alternate read host to Server 3.... all good now Smiley Happy