Hi Igniters, I've updated page with more detailed info about WAL and NativeIO, added references to system properties.
Denis, thank you for noticing unclear section. Sincerely, Dmitriy Pavlov ср, 21 мар. 2018 г. в 2:18, Raymond Wilson <raymond_wil...@trimble.com>: > Denis, > > Thanks for the clarification on read-intensive workloads not being suitable > for Direct IO. > > As a counterpoint to that, I would have thought the working set represented > by the in-memory data held by the Ignite node would be significantly larger > than the OS page cache which should mean the read hit rate on the OS page > cache would be very low under those workloads? Of course, this assumes your > WAL page size is configured to be similar to the OS page size, but > still.... > > -----Original Message----- > From: Denis Magda [mailto:dma...@apache.org] > Sent: Wednesday, March 21, 2018 11:59 AM > To: dev@ignite.apache.org; Prachi Garg <pg...@gridgain.com> > Subject: Re: Ignite Direct I/O plugin description added to wiki > > *Dmitriy*, thanks. Astonishing job! We'll add a section to the durable > memory tuning page and refer to the wiki for more details: > https://issues.apache.org/jira/browse/IGNITE-7466 > > Please clarify the following: > > > Direct I/O mode can't be enabled for Write Ahead Log files. However, > > when working with plugin, WAL manager applies advising Linux systems > > do not store the data of the file in page cache as they are not required. > > > For me, it means that WAL always goes through the operating system I/O > calls. Nothing changes for the WAL. However, I'm not sure what you meant to > explain by saying "when working with the plugin (Direct I/O) WAL manager > applies...". Could you rephrase it to bring more clarity? > > *Raymond,* > > If Direct I/O is enabled by default it will bring down the performance of > read-intensive application because, as Dmitry says, the reads bypass page > cache. So, I would recommend using it for write-intensive workloads and, > probably, for mixed-workloads depending on the reads and writes rate. > > -- > Denis > > > On Tue, Mar 20, 2018 at 2:29 PM, Raymond Wilson < > raymond_wil...@trimble.com> > wrote: > > > Looks good! > > > > Is there any reason why this should not be a default setting if it > > gracefully downgrades to non-Direct IO if not supported by the OS? > > > > Thanks, > > Raymond. > > > > -----Original Message----- > > From: Dmitriy Setrakyan [mailto:dsetrak...@apache.org] > > Sent: Wednesday, March 21, 2018 10:23 AM > > To: dev <dev@ignite.apache.org> > > Subject: Re: Ignite Direct I/O plugin description added to wiki > > > > Thanks Dmitry, awesome work! > > > > On Wed, Mar 21, 2018 at 12:21 AM, Dmitry Pavlov > > <dpavlov....@gmail.com> > > wrote: > > > > > Hi Igniters, > > > > > > I've added description of new plugin for Direct I/O for native > > > persistence ( > > > https://issues.apache.org/jira/browse/IGNITE-6341) to wiki > > > https://cwiki.apache.org/confluence/display/IGNITE/ > > > Ignite+Persistent+Store+-+under+the+hood#IgnitePersistentStore- > > > underthehood-DirectI/O > > > > > > > > > SIncerely, > > > Dmitriy Pavlov > > > > > >
