Re: [Veritas-bu] NetBackup 6.5 index size

On Fri, Mar 28, 2008 at 8:03 AM, Dariusz Klar <Dariusz.Klar AT sun DOT com> wrote:

I know the general rules, but... Another challenge for me is to estimate
disk space for NetBackup catalog where total amount of data under
NetBackup protection is 3.6 PB (peta bytes) with ability to grow to 8.5
PB in the future.

Yes, size matters. but if that 3.6PB consists of 10k tiff files (and I would feel your pain!), your catalog would be significantly larger than if it consists of 100GB Oracle tables.

The difference between 1% and 2% of total amount of protected data for
catalog does matter. The difference vary from 36 TB to 85 TB in case of
1% difference. I need to be more precise. If I will say to my customer
that they have to buy 255 TB (3% of total amount of data in the future)
for NetBackup catalog, I have to be 100% sure what I'm talking about.

I called Symantec and with that big data volume they are not 100% sure
about space size for NetBackup catalog.

Data volume does not matter - the number of unique filenames does. I could design the application to put 100 files in 100 directories and end up with a much larger catalog than if I put those 10,000 files in a single directory.

If the data is all transitory and your retentions are long, the catalog will be much larger than if the data was fairly stagnant or retentions short. My Exchange environment is about 3TB or so and my catalog for that is about 2.2MB - that's under 0.01%. I have about the same amount of disk space in an environment that has host-based mirror sets, longer retentions, more transitory data, and small files. The catalog for that is 25GB - 1,000 times larger for the same amount of disk space. Even that is only 0.8% of allocated disk space. I have a 27TB application that requires 147GB of catalog space - about 0.5% - and it too has lots of little files.

My total catalog size is under 600GB and we have about a 340GB of allocated disk space (that's SAN based and doesn't count the servers with local disk space or volumes that have host-based mirrors). That's about 0.2% of allocated space, nowhere near the 1-3% that you've been looking at. Again, how you use and back up your data will have a very significant impact on your catalog size.

If your customer can tell you exactly how they're going to use the disk space and what their backup policies and retentions are going to be, then you can be more accurate in calculating a catalog size. If they can't, you're not going to have enough information to make a useful prediction.

--
Ed Wilts, Mounds View, MN, USA
mailto:ewilts AT ewilts DOT org

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