Add block information to status page and info

[pjeli]

There is a feature request to open up the information that NNA produces to beyond files but also include some block information.

On the main status page showing small files, etc, would be neat to also see:

• Number of total blocks
• Number of total replicas (blocks times replication factor)
• Average block size
• Histogram the metrics above per user

All the filters and summations are already in place; just need to compute and expose it as we have with other information.

[pjeli]

I think this one may need some stepping back for a time due to the possibility of the information changing with respect to Erasure Coding contiguous block in HDFS 3.0+.

[pjeli]

It is debatable if this is necessary anymore as this can be achieved simply with cached queries. Though perhaps some folks may still want to see this information on the main status page, /suggestions.html.