- So what I understand you are doing is using the SLP to get around the 
boundaries of tape pools being assigned to a given media, this way all the data 
gets backed up by a pool of all of the tapes as one group?  
- Yes, we backup to disk into one or two pools, with a short retention (SLP 
actually sets retention to infinite so no danger of losing data, then reverts 
to short retention, so it expires and the tape becomes the active primary copy)

- I assume vault is the underlying technology but the SLP is just the layer at 
which you configure and run it all.  Do you need the Shared Storage Option for 
this?
- Nope - only if you want to share drives. 

- In your experience does the data get split across all of the drives evenly?  
If one tape finishes its list of images does it just sit there or does NBU find 
more data for it to backup? (similarly to how the resource manager would do 
when we used to copy straight to tape)?
- Yes, it balances across drives well. You have to do some parameter 
configuration in terms of how large a backup to write immediately or how long 
to wait before duping to optimize this.

- I guess this could help keep my drives spinning, won't do much for my speed 
issue but it seems like it could help with the data allocation... thanks for 
your advice.
- You are welcome.


 

Date: Tue, 28 Jul 2009 14:16:07 -0400
From: jkearns <netbackup-forum AT backupcentral DOT com>
Subject: [Veritas-bu]  Vaulting images from disk = slow tape speed,
        ideas???
To: VERITAS-BU AT MAILMAN.ENG.AUBURN DOT EDU
Message-ID: <1248804967.m2f.311641 AT www.backupcentral DOT com>



> We backup about 16Tb of data over the course of a weekend. We used to run NBU 
> 6.0 MP2 with four LTO3 drives fiber connected. We recently changed to NBU 
> 6.5.3 and a disk to disk appliance... we now vault from the disk images (DSU) 
> to tape for offsite storage and DR. By my estimates the drives used to copy 
> at roughly 62 Gb/Hr multiplexed. So we would be finished over the course of a 
> weekend. Now that we are vaulting from disk to tape, the tape drives cannot 
> multiplex from disk to tape. My vault jobs take extremely long to finish and 
> if a drive is busy when the vault job begins then it only runs on the 
> remaining available tape drives (which for us, we have two tape storage 
> groups with two drives in each one based on what master/media they belong to) 
> so when something happens to one drive I end up copying images for half of my 
> environment to one tape drive. The drive non-multiplexed are copying at about 
> 30-35 Gb /Hr. Moving to a disk replication would solve this but my DR plan 
 is a cold site so I have to keep tape. Is there anything I can do to improve 
this performance?
> 
> *********************
> 
> This is exactly what I found, and SLP (storage lifecycle policies) are my 
> solution. 
> You set up the SLP to backup to disk pool A as step one, and have a second 
> step that copies that from disk to tape pool B with your normal retention. 
> Essentially you get a one tape drive vault process, and no longer lose your 
> efficiency. 
> 
> *********************
> 
> So what I understand you are doing is using the SLP to get around the 
> boundaries of tape pools being assigned to a given media, this way all the 
> data gets backed up by a pool of all of the tapes as one group?  I assume 
> vault is the underlying technology but the SLP is just the layer at which you 
> configure and run it all.  Do you need the Shared Storage Option for this?  
> In your experience does the data get split across all of the drives evenly?  
> If one tape finishes its list of imiages does it just sit there or does NBU 
> find more data for it to backup? (similarly to how the resource manager would 
> do when we used to copy straight to tape)?
> I guess this could help keep my drives spinning, won't do much for my speed 
> issue but it seems like it could help with the data allocation... thanks for 
> your advice.
> 


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