If you’re a longer term NetWorker user, you’re used to a particular number: 160.
The NetWorker performance tuning and optimization guide (included with the standard NetWorker documentation set) tells us that on average, 160 bytes of index space is used for each browsable file in the NetWorker index. Note that this applies to conventional filesystem backups (and is a reasonable approximation for NDMP backups). For database backups, block based backups of filesystems, and image based backups of virtual machines, the index size is always quite small, comparatively.
We can use this to calculate approximately how much space a filesystem client will need for its indices on the NetWorker server. The rule of thumb I tend to use is: for most clients, the daily incremental backups will not really contribute to the overall index size. In reality it’ll be the weekly fulls, monthly fulls and (if you use them), yearly fulls that contribute to the index size over time.
To get a feel for what that can be like, check out the sample calculator below.
I’ve split out the calculations above so you can see how it works. (I’m also using base 10 for the conversion between bytes to MB, and bytes to GB — e.g., 1000 MB = 1 GB.)
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