[ClusterLabs] Q: About a false negative of storage_mon

[井上和徳]

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