>>> "Ulrich Windl" <ulrich.wi...@rz.uni-regensburg.de> schrieb am 03.08.2022 um 08:02 in Nachricht <62ea0f62020000a10004c...@gwsmtp.uni-regensburg.de>: >>>> Ken Gaillot <kgail...@redhat.com> schrieb am 02.08.2022 um 16:09 in > Nachricht > <0a2125a43bbfc09d2ca5bad1a693710f00e33731.ca...@redhat.com>: >> On Tue, 2022-08-02 at 19:13 +0900, 井上和徳 wrote: >>> Hi, >>> >>> Since O_DIRECT is not specified in open() [1], it reads the buffer >>> cache and >>> may result in a false negative. I fear that this possibility >>> increases >>> in environments with large buffer cache and running disk-reading >>> applications >>> such as database. >>> >>> So, I think it's better to specify O_RDONLY|O_DIRECT, but what about >>> it? >>> (in this case, lseek() processing is unnecessary.) >>> >>> # I am ready to create a patch that works with O_DIRECT. Also, I >>> wouldn't mind >>> # a "change to add a new mode of inspection with O_DIRECT >>> # (add a option to storage_mon) while keeping the current inspection >>> process". >>> >>> [1] >>> >> > https://github.com/ClusterLabs/resource-agents/blob/main/tools/storage_mon.c
> # > >> L47-L90 >>> >>> Best Regards, >>> Kazunori INOUE >> >> I agree, it makes sense to use O_DIRECT when available. I don't think >> an option is necessary. >> >> However, O_DIRECT is not available on all OSes, so the configure script >> should detect support. Also, it is not supported by all filesystems, so >> if the open fails, we should retry without O_DIRECT. > > I just looked it up: It seems POSIX has O_RSYNC and O_SYNC and O_DSYNC) > instead. I missed an opening paren: "I just looked it up: It seems POSIX has O_RSYNC (and O_SYNC and O_DSYNC) ..." > The buffer cache handling may be different though. > > Regards, > Ulrich > >> -- >> Ken Gaillot <kgail...@redhat.com> >> >> _______________________________________________ >> Manage your subscription: >> https://lists.clusterlabs.org/mailman/listinfo/users >> >> ClusterLabs home: https://www.clusterlabs.org/ > > > > _______________________________________________ > Manage your subscription: > https://lists.clusterlabs.org/mailman/listinfo/users > > ClusterLabs home: https://www.clusterlabs.org/ _______________________________________________ Manage your subscription: https://lists.clusterlabs.org/mailman/listinfo/users ClusterLabs home: https://www.clusterlabs.org/