In general, reading an entry from bookie is pretty fast as most of the index pages will be cached in memory, so it typically only needs one disk access.
You might see evaluated latency when index pages begin swapping in and out. So ideally I would suggest using small index page size and large memory, so you can keep most of the index pages in memory. - Sijie On Wed, Aug 3, 2016 at 7:10 AM, Enrico Olivelli <eolive...@gmail.com> wrote: > Hi BookKeepers, > > Recently JV explained how BookKeeper can support a long term > low-latency data store. > > I'm working on a new project which need a fast replicated "object > store" on local LAN, replication is needed only for high-availability. > > Usually the object (byte[]) size will be between 10KB and 10MB and > typically they are kept only for a couple of days, for a medium total > storage size of 700GB. > > My idea is to write these objects to BookKeeper and store the entry > coordinates (ledgerId/offset) as a pointer to the object. > > My question is about random access reading from Bookies, can I hope to > achieve low latency while reading a single entry from a ledger ? > > Both writes and reads will run concurrently with an high degree of > parallelism (thousands of concurrent writes/reads) > > In my use case it is very likely that reads will be done on recently > written data, so I think that the bookie cache would come to help > > What do you think ? >
