Pulling this sentence out from much earlier in the thread; "N should be set to the number of nodes."
That's not true and our docs should not say it today or be changed to say it in the future. N is how many copies of a document we'll maintain. If you had a 20 node cluster, you would not want 20 copies of every document. The default of 3 copies would be sufficient to prevent accidental loss. B. > On 4 Oct 2019, at 23:55, Joan Touzet <woh...@apache.org> wrote: > > Thanks for the follow-up. Thinking of >1 active DB per host makes this > calculation a lot more challenging. > > Sounds like our recently merged default change of q=2 will be fine. > > -Joan > > > On 2019-10-04 17:40, ermouth wrote: >> This tuned out to be interesting, results vary heavily for different >> platforms. >> >> I included `perftest.html` into Photon design doc. The utility gives good >> insight how q,n impact doc creation, doc update, validate + update, and >> viewindex create/update – for a particular CouchDB instance. >> >> Common observations: >> * q=1 is only ok for rare special cases (like DBs with dozen docs) >> * it’s ok to have q==cores or q==cores+1 or even cores+2: write perf drops >> a little, but viewindex update is bit faster >> * excessive q (say, more than cores×2) negatively impacts direct write >> perf: having q8 for 2core at least halves write perf for most >> commodity/lean platforms and hw cfg. >> >> ermouth >> >> >> чт, 11 июл. 2019 г. в 18:17, Joan Touzet <woh...@apache.org>: >> >>> On 2019-07-11 8:05, ermouth wrote: >>>>> to help with the documentation step >>>> >>>> Probably. Please give me a hint what you need. >>> >>> What default settings right now are wrong for a system with low RAM, low >>> CPU, and slow disk - such as a RaspberryPi v1, or a $15/mo AWS server? >>> >>> -Joan >>> >>> >> >
