Update experiments-msmarco-v2.md
Added note about pyserini support and AzCopy
This guide presents information for working with V2 of the MS MARCO passage and document test collections.
+If you're having issues downloading the collection via `wget`, try using [AzCopy](https://docs.microsoft.com/en-us/azure/storage/common/storage-use-azcopy-v10).
+
Indexing the passage collection, which is 20 GB compressed:
```
@@ -60,6 +62,9 @@ recip_rank all 0.1572
recall_100 all 0.5956
```
+Currently (06/26/2021), indexing doesn't work in [Pyserini](http://pyserini.io/) yet (will work once we push next release).
+However, Pyserini _can_ work directly with an index built in Java by Anserini; just pass the index path to `SimpleSearcher`.
+
## Reproduction Log[*](reproducibility.md)
