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VTL Performance Best Practice

  • 23 August 2021
  • 3 replies
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Hi,

has anyone experiences with VTL self Deduplication Backup Appliances, like Quantum DXi4800 for Example (smaller Modells ~27 TB)? The deveices are non Deduped backuptargets for commvault. Later Aux-Copy to a physical Tape-Library is performed.

I got a Performance Best Practice Guide from Quantum. They said use small cartridge size 50/100 GB (like Ultrium 1) but not how many Tape Deveices in parallel and how this relates in backup and restore performance. 

To much Tape-Drives maybe slow down the throughput but i have no idea which throughput per drive stream is possible comparred to a physicale tape drive which normaly only receive 100-200mb/s.

Would be nice if someone else use this "old"stuff and can explain something in correlation with commvault. My last VTL implementation was 10 years ago.

Thanks
Christoph

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Best answer by Christo 25 August 2021, 09:35

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Userlevel 7
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Hey @Christo,

VTL … just wont die huh? :joy:

Just as with disk backups, ‘it depends’. The great thing is that you should be able to scale up and scale down the number of drives. It may take some experimentation to find the sweet spot. The ‘old’ recommendation is two streams per spindle (magnetic drive), if you know how many disks back your VTL you could use that as a starting point. Using stream limits in your storage policies, you can very easy increase or throttle usage regardless of how many drives you allocate.

More of art than science … but you don't have to lock yourself in out the gate to a specific number.

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Hi Damian,

 

yes, it was outdated technic 10 years ago... but some customers don’t like to change anything…

 

It is the smallest DXi4800 package, so two 6 x 4TB Raid 6, maybe with one hotspare for each Raid, so i think 10 total Drives.

The old VTL uses 6 Tape Deveices. I will start with that and maybe increase the Drives Number and see what happens. :)

 

Thanks

Userlevel 7
Badge +23

Hi Damian,

 

yes, it was outdated technic 10 years ago... but some customers don’t like to change anything…

 

 

You know, I was walking onto an aircraft on Monday and noticed the date of manufacture was 2002 - and I thought, probably better than something brand new. On the return flight, a newer plane required a software update and left us on the tarmac for 1.5 hours…. so in some scenarios I totally get it :rofl:

 

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