Shouldn't the OS care of defragmentation? What we need to do is to give a way to remove stale data and "release" the allocated space somehow through the tools, MBeans or API methods.
-- Denis On Fri, Dec 28, 2018 at 6:24 AM Vladimir Ozerov <voze...@gridgain.com> wrote: > Hi Vyacheslav, > > AFAIK this is not implemented. Shrinking/defragmentation is important > optimization. Not only because it releases free space, but also because it > decreases total number of pages. But is it not very easy to implement, as > you have to both reshuffle data entries and index entries, maintaining > consistency for concurrent reads and updates at the same time. Or > alternatively we can think of offline defragmentation. It will be easier to > implement and faster, but concurrent operations will be prohibited. > > On Fri, Dec 28, 2018 at 4:08 PM Vyacheslav Daradur <daradu...@gmail.com> > wrote: > > > Igniters, we have faced with the following problem on one of our > > deployments. > > > > Let's imagine that we have used IgniteCache with enabled PDS during the > > time: > > - hardware disc space has been occupied during growing up of an amount > > of data, e.g. 100Gb; > > - then, we removed non-actual data, e.g 50Gb, which became useless for > us; > > - disc space stopped growing up with new data, but it was not > > released, and still took 100Gb, instead of expected 50Gb; > > > > Another use case: > > - a user extracts data from IgniteCache to store it in separate > > IgniteCache or another store; > > - disc still is occupied and the user is not able to store data in the > > different cache at the same cluster because of disc limitation; > > > > How can we help the user to free up the disc space, if an amount of > > data in IgniteCache has been reduced many times and will not be > > increased in the nearest future? > > > > AFAIK, we have mechanics of reusing memory pages, that allows us to > > use pages which have been allocated and stored removed data for > > storing new data. > > Are there any chances to shrink data and free up space on disc (with > > defragmentation if possible)? > > > > -- > > Best Regards, Vyacheslav D. > > >
