Hi Alex, I wonder what problem you wish to solve. Pre-touching memory looks like a solution. But what is the problem? Am I getting it right that it is desired to avoid OOM (of some kind) in unpredictable moment of Ignite process execution? If so there could be number of ways to tackle it.
I am not aware of means which can reserve physical memory for a process in such way that particular process will "own" that memory exclusively. Pre-touching might not give such guarantees. Actually, I think that one who deploys failure critical system should carefully plan resources allocation. I agree with Andrey here that it is worth adding some foolproof check. In my mind it could be even preventing a node startup if a requested data region size is greater than an estimated amount of available memory. And if such check (by some unusual reason) is not needed it could be disabled with some property. ср, 24 окт. 2018 г. в 14:41, David Harvey <syssoft...@gmail.com>: > Denis, > > We run must of our production DBs systems without any swapping space, > because the 10-100x drop in throughput if such systems start paging makes > them worse than useless. However, we don't get OOM on them until all the > pages are dirty, since LINUX will page out read-only (code) pages or memory > mapped files. > > Dave Harvey > > > > On Wed, Oct 24, 2018 at 12:12 AM Denis Magda <dma...@apache.org> wrote: > > > Alex, > > > > Correct me if I'm wrong, but even if an OS runs out of physical memory (X > > GB in total) an Ignite node process still can request the X GB from > virtual > > memory. Yes, virtual memory can involve swapping and disk to satisfy your > > request but this shouldn't be a reason of the OOM. Shouldn't OOM happen > if > > you're trying to allocate beyond the virtual memory capacity (beyond X > GB)? > > > > Denis > > > > On Tue, Oct 23, 2018 at 12:08 PM Gerus <age...@gridgain.com> wrote: > > > > > Hi *Igniters*, > > > Some time ago I've raised a suggestion for product improvement > > > https://issues.apache.org/jira/browse/IGNITE-9112 > > > <https://issues.apache.org/jira/browse/IGNITE-9112> . It's all about > > > off-heap memory allocation. Current implementation can have some > > > improvements for failure critical systems. Ignite can have OOM in > > runtime, > > > because RAM can be used by OS, if it will not be pre-booked by > operation > > > system and this proposal is to address that. Common case is offheap and > > > thats why memory segment cannot be managed by JVM that has > > +AlwaysPreTouch > > > option > > > Obviously this implementation will make startup longer and thats why it > > is > > > proposed to use configuration flag to manage this feature > > > I think, it will be useful to have this option. Are you supporting > this? > > > > > > > > > > > > -- > > > Sent from: http://apache-ignite-developers.2346864.n4.nabble.com/ > > > > > > -- Best regards, Ivan Pavlukhin
