Should my shard allocation strategy take available CPUs into considerations?
When using a mutli processor machine, I saw a serious slow down in indexing and query speeds when using 1 shard, while getting much better speeds when allocation 4 shards (machine has 8 CPUs).
If I have 1 shard, does that mean that I can only use one bulk/search thread for that index? Does using multiple shards have an impact on disk I/O? (I was under the impression that writing to 1 file will produce the same results as writing to 4 files in terms of disk I/O, am I wrong?)