I've been reading about BlueStore and I came across the BlueStore Cache
and its ratios. I couldn't fully understand it.

Are .99 KV, .01 MetaData and .0 Data ratios right? they seem a little
too disproporcionate.
Also .99 KV and Cache of 3GB for SSD means that almost the 3GB would be
used for KV but there is also another attributed called
bluestore_cache_kv_max which is by fault 512MB, then what is the rest of
the cache used for?, nothing? shouldnt it be more kv_max value or less
KV ratio?

I know it really depends on the enviroment (size, amount of IOS,
files...) but all of this data seems to me a little too odd and not
razonable.

Is there any way I can make an aprox about how much KV and metadata is
generating for GB of actual data?

Does it make anypoint to left some cache for the Data itself or its
better to just store ONodes and metadata?

Another little question
I dont really understand how BlueStore gets its speed from cause it
actually writes the data directly to the end device (not like FS where
you had a journal), then... shouldnt speed be limitated for that device
write speed even having a SSD for RocksDB?

Thanks a lot.

------------------------------------------------------------------------
*Jorge Pinilla López*
jorp...@unizar.es
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