Support #18894
closed[document] how Keep manifest size can be predicted/calculated
Description
Peter wrote this up a while ago, it should be added to the documentation at https://doc.arvados.org/architecture/manifest-format.html
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Here's a formula for estimating manifest size, assuming efficiently packed blocks. This is including the block signatures, which makes it bigger than the size of the manifest in the database, because that is what is actually transferred to/from the API server and stored in RAM by arv-mount.
sum(size of all directory paths)
+ (total data size / 64 MB) * 94
+ sum(size of all file names)
+ sum(number of files * 20)
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