On Tue, Aug 2, 2022 at 4:10 PM Ken Gaillot <kgail...@redhat.com> wrote: > > 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.
Might as well be interesting to adjust block-size/alignment to the device. Another consideration could be to on top directly access the block-layer using aio. Both is being done in sbd (storage-based-death) and yes it as well adds Linux specific stuff that might have to be conditional for other OSs. Klaus > > 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. > -- > 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/
