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Using NetBackup BasicDisk instead of PureDisk as DiskType ...

Level 4


as far as I understand, it's also possible to backup VMs with NetBackup 8.0 to a backup-to-disk folder (DiskType BasicDisk) instead of an MSDP backup-to-disk folder (DiskType PureDisk).

What is the big difference between using a backup-to-disk-folder (DiskType BasicDisk) on a Windows 2012R2 server with deduplication enabled on an NTFS partition (where deduplication takes places at a later time after data was written) and the use of a backup-to-disk folder (DiskType PureDisk), where deduplication takes place in RAM before data is written to the MSDP pool or PureDisk backup-to-disk folder?

If a backup-to-disk folder (DiskType BasicDisk) is used on an NTFS partition on a Windows 2012R2 server without deduplication enabled, backup data that's written to this folder should occupy the same amount of data, as the backup size of the corresponding VM, right?

So in the case of using a backup-to-disk folder (DiskType BasicDisk), no licenses ...


... are required, right?

Regards, Didi



Level 5

That is not necessary correct.  NetBackup MSDP or PureDisk use a plugin with a stream handler that performs special handling on VMware backups (for example).  To maximize the deduplication that you will get using standard Deduplication from any other product.  Also in the event of corruption on the Windows NTFS Deduplication there is no telling what type of data loss you might see.

Ok, so instead of using PureDisk or MSDP (for which a license is required in NetBackup), we can just use a BasicDisk as DiskType (pointing it to a standard folder on an NTFS partition) and not use deduplication of Windows Server 2012R2 (provided enough disk space is available) and save the costs for a license, right?

Therefore, we can save our backups to the defined NetBackup BasicDisk (backup-to-disc folder) first, before we put everything on tapes in our tape-library.

Is there any difference, in what is saved to a tape media, when it was originally put into a PureDisk or a BasicDisk backup-to-disc folder? Or in other words, is it absolutely save to first backup any kind of data (e.g. Virtual Machine data from a vSphere environment) to a BasicDisk, before saving it to tape media later?

Is those data in PureDisk backup-to-disc folder, which is saved to a tape media later, still deduplicated?

Any answer is much appreciated. Thanks in advance.



Additionally to my last questions, I have another question ...

Is it save to backup VMware vSphere virtual machines to a backup-to-disc folder (DiskType BasicDisk) in one file (if NTFS is used as filesystem), instead of cutting down the backup files into 2GB chunks?

The first test backup into a BasicDisk backup-to-disc folder created several files for only one selected VMware vSphere virtual machine in the source environment. Then I created another BasicDisk backup-to-disc folder and deselected 'Reduce fragment size' and it resulted in 6 files in total, if I recall correctly.

Are there any meaningful reasons to cut down the backup files into several chunks in an NTFS partition?

Thanks again for any input.


Level 6
Partner    VIP    Certified

Yes plain BasicDisk (is DSU or DSSU) form is safe for use as storage unit target for any source of NetBackup Client backup data.  Any.  As long it comes from a NetBackup Client, then BasicDisk is safe (assuming the hardware config is safe).

I cannot comment on whether using NTFS native dedupe is safe or not.  Or allowed or not.

You can experiement with fragment size, but really you don't want it so small that you end up with millions of files inside the BasicDisk storage unit.  Is there any reason why the default doesn't work you?  Why would you want to change it?  The fragment size doesn't make really make any performance difference at all for disk storage units.  For disk it's just a unit of container size, it's not even a unit of measure.  There is no space saving to be had my making it smaller.  Here's a tip: don't change NetBackup setings without a good well thought and proven reason.  And document any changes, in the correct order, in your "NetBackup environment rebuild plan" document.

It doesn't matter if fragmnt size is different between DSU/DSSU and tape.  The duplication stage will take care of it.

AFAIK you cannot use SLP with BasicDisk.  FYI there are two modes of BasicDisk.  One mode is DSU, Disk Storage Unit, i.e. plain BasicDisk with no added functionality.  The othe rmode is DSSU, Disk Storage Staging Unit, with added functionality which leverages the LWM (Low Water Mark) and HWM (High Water Mark) to cause the desired duplication to tape behaviour that you want to see happen.  i.e. you have to stop, think, and plan what it is you want to see happen, and so adjust your LWM and HWM accordingly to achive what "you" want.  DSSU is it not magic, it doesn't just do its thing on its own - instead you actually have to think about it, and set it correctly.

Performance difference?  Worse, better?  Who knows.  It all depends upon the capabilities of disk and how you use that disk (i.e. your workload patterns).


Also be aware NetBackup licensing requires a Data Protection Optimization (i.e. Deduplication) license for any storage target that performs deduplication. NetBackup can be installed and will run using BasicDisk on a NTFS Dedupe folder without a Data Protection Optimization key but you will be outside the EULA. So actually there is no license cost saving in which case I believe you would be way better off to use MSDP. BR Andrew

Ok, let me be more precise again:

Completely forget about deduplication in Windows Server 2012R2 at all !!!

I thought 'Reduce fragment size to' creating a new Storage Unit is selected by default, that's why I orginally asked that question. No, I don't want to end up with millions of files, so I will keep the default, when using a BasicDisk as backup-to-disc folder.

This will end up in 6 files per vSphere virtual machine ... & file (with the VM data inside) & file () & file ()

That's enough for 1 virtual machine!

Ok and last but not least those 2 questions ...

1) Is there any difference, in what is saved to a tape media, when it was originally put into a PureDisk or a BasicDisk backup-to-disc folder?

2) Is those data in PureDisk backup-to-disc folder, which is saved to a tape media later, still deduplicated?



Partner    VIP   

Please remember:

NTFS deduplication is a post operation process, it is not inline as with MSDP.

When new files are added to the volume, they are not optimized right away. Only files that have not been changed for a minimum amount of time are optimized. (This minimum amount of time is set by user-configurable policy.)

Now consider to move large amount of backup data into a NTFS dedupe volume during backup ..

Yes, that's why I said, I will use a big NTFS partition instead and do not use deduplication, but a BasicDisk DiskType in NetBackup instead of an MSDP pool to save license costs.

And as backup-to-discs backup using a BasicDisc in NetBackup and without deduplication is not against the EULA of NetBackup, I should be save, right?


Level 6
Not really.. There is not much difference when the image goes to tape from either of the disk (although in the background rehydration of the image occurs when its going from msdp to tape and could take a little longer if the image is scattered in msdp)

The deduplication is only on msdp.. tape copies would always be plain n simple copy..

Just for an example:
Say your vm is somehwere around 500 gb in size
You ran the policy 4 times

scenario 1
>> backup to basic disk and duplication to tape
on basic disk
>> 4 copies would make it around 2TB

on tape
>> 4 copies again would make it 2TB

scenario 2
>> backup to msdp and duplication to tape

on msdp
>> 4 copies but data stored would be less than 500 gb (you end up saving more than 1.5 TB of space and can continue running more backups as well)

on tape
>> 4 copies (rehydrated from msdp) and would use around 2TB as earlier..

So if you planning on just keeping 1 copy on disk and immediately duplicating it to tapes then basic disk seems fine but if you planning on keeping more copies on disk then you would need to take a call whether you would like to spend money on the license and save on disk storage or spend more money on disk storage because eventually basic disk would be filled up if u run multiple backups especially with higher retention unless of course you have DSSU configured to move the data off to tapes when filed up..

Hello Amol_Nair,

ok, first of all thanks for replying regarding what ends up on tape and that data is the same, whether it comes from a BasicDisk or PureDisk. Data is not deduplicated, when it is duplicated from PureDisk to a tape media.

Of course if backup of a VM is done 4 times full, you end up with 4 times the space used, when using a BasicDisk. Instead of using full backups, I would use one full and subsequent cumulative backups. Also this would end up in more space occupied in a BasicDisk, than in a PureDisk backup-to-disc-folder.

So doing full and cumulative backups to a BasicDisk (on an NTFS partition without deduplication enabled) and duplication to a tape media later is fine and fully supported in NetBackup. PureDisk requires an additional license, which saves me some space on a backup-to-disc folder, but not on tape media. There are some other advantages with an MSDP pool as well, but BasicDisk is fine as well and fully supported.

Without an MSPD pool license, I need more disk space, but that's fine as well. Data on a BasicDisk is as save as in a PureDisk backup-to-disc folder.

Maybe there is more budget available in the future to spend money on an MSDP pool license, but as long as there is enough disk space available using a BasicDisk, I suppose, we will got that way to save some license cost.

And as using a BasicDisk as a backup-2-disc folder on an NTFS partition without deduplication enabled is fully supported in NetBackup, we are fine with this method for the time being.

Regards Didi