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multiple backup streams to single drive

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Hi,

 

I am thinking of using one of our Overland Storage Neo Series 2000 LTO-2 tape libraries with Retrospect 6.5 MS - I am struggling to find out if you can run multiple backup streams to a single drive (with or without ATS) although I realise you can run multiple streams concurrently to seperate drives or disks.

 

The reason I am asking is that using Arkeia I can get nearly 3000MB/min sustained out of a single drive (LTO-2) - using multiple streams across the network. Each single stream is far slower than this (1/3 to 1/10 ). If Retrospect can only write one stream at once to this single drive then it will be far too slow to use the drive effectively.

 

Alternatively are there any other ways of using Retrospect to get the maximum performance of the drive (we are talking about 3TB of data for a full backup so copying data locally is not an option).

 

regards

simon

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Hi

 

This will not work. You can only backup once source to one backup set at a time. This boils down to one drive, one source.

 

Nate

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thanks for your reply,

 

In that case is there any decent way to maximise performance with a high speed drive. Even a backup from a local drive could be a lot slower than the tape drive speed if the server is quite busy (as ours are most of the time) and certainly most network backups are far slower than this in my experience. I can't really see how retrospect can take advantage of the speed of these devices without doing multiple streams - or am I missing something ?

 

regards

 

simon

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Simon,

 

I don't think you're missing anything, and I think you gave the answer in your first post: installing a secondary drive into the Neo will probably double the amount of data that you can back up in a fixed time frame.

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It you have a tape library that contains two tape drives you can stream different sources to them simultaneously with the Advanced Tape add-on. It would have to be two different sources to two different backup sets, but it will run multiple executions with Retrospect 6.5 and the tape add-on.

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Quote:

Hi

 

This will not work. You can only backup once source to one backup set at a time. This boils down to one drive, one source.

 

Nate

 


 

Hi.

 

I can't find this in the manual. In fact, on page 105 in the Win 6.5 manual it says you can have multiple executions. In addition, if you also have multiple drives, you can use them simultaneously.

 

VERITAS Backup Exec™ for Windows Servers can do this (but this product has other drawbacks).

 

Regards

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Hi

 

You can backup different sources to different tape drives with multiple executions (up to eight to be exact) however you cannot interleave data/ backup multiple sources to the same tape drive at the same time.

 

In other words, you can run multiple backups at once but you need a seperate backup device for each source

 

Nate

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Quote:

...

you cannot interleave data/ backup multiple sources to the same tape drive at the same time.

...

Nate

 


Hi.

 

That's what posters in this thread says, but that's not what the manual says. See page 105 in the Win 6.5 manual as I wrote earlier.

If this thread is correct, the multiple backup units are useless to the normal users. How can you possibly saturate the average tape station if you can't pull from multiple clients at the same time???

 

Regards

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Lennart has my point exactly - I could add another drive to our library ($$$) meaning I can backup approx twice as much data in the same time frame - but I am still only using a small percentage of the tape drives capability. If I have buy two drives then I would be wasting even more money. I would be better buying slower/cheaper tape drives.

 

I am not sure that the manual says is possible however. I read the manual as saying multiple backup units to different destinations (multiple drives if you buy ATS). Which is what natew and amy (and powermeck) are saying. I agree, however, that multiple backup units are useless for situations where you only have one tape drive (no matter how fast !) in your system.

 

I realise this limitation but I think that it is quite poor for an enterprise class product. As I mentioned before this implies that retrospect will not really be ideal for fast tape drives especially in network environment. Other software (www.arkeia.com) does this effectively meaning I can backup nearly 3 times faster with the same hardware. I suggest that this is something that Dantz should take a look at - tape drives are getting faster all the time.

 

I hate to use message boards for whingeing but it does seem that Dantz's response seems to be of the 'buy more drives' variety - not 'maximise what you have'.

 

si

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