Thanks for the answer, Dave! Are you aware if there are any plans for distributed TDB?
Stefan P.S. In that order of thinking On 9/22/17, 12:39 AM, "Dave Reynolds" <[email protected]> wrote: On 22/09/17 00:58, Dimov, Stefan wrote: > I’ve got two questions: > > 1. The documentation of Jena/TDB states that the replication of the DB > is possible, just by copying the TDB files. (I tried that, it’s > working.) It also states that the copying should be done ONLY while > the Fuseki server is stopped, even if there’s no writing in TDB > (just reading). Is that true? Is it not possible to replicate TDB > without stopping the nodes? In practice, if there's no writing going on, then I've not had it fail and seems like it should work, but not something we've used in production. It would need someone more expert to say why it could be an issue for a read-only workload. One thing, make sure you delete the lock file (used to prevent multiple jvm's reading the same file set). > 2. We’re considering this architecture: Multiple virtual nodes running > separate instances of Fuseki and all of them using TDB, which is > residing on a shared file system Note there's no attachments on this list so no embedded images. > Would it be possible? Are there going to be any concurrency issues? What > if there’s read operations only? You can't have multiple TDB instances in different JVMs using the same file set, TDB creates a lock file with the PID in, to prevent this. In any case performance depends largely on disk speed so replicating the data to each instance and using fast local storage is generally a better plan than running off slower, shared network storage. Dave
