On Fri, 2020-03-06 at 10:56 -0600, Ron wrote: > > > > RAC is not really a high availability solution: because of the shared > > > > storage, it has a sibgle point of failure. > > > This is utter nonsense. Dual redundant storage controllers > > > connected to disks in RAID-10 configurations have been around for at > > > least 25 years. > > > > > > Oracle got it's clustering technology from DEC, and I know > > > that works. Cluster members, storage controllers and disks have all > > > gone down, while the database and application keep on humming along. > > > > I am not saying that it is buggy, it is limited by design. > > > > If you have mirrored disks, and you write junk (e.g, because of > > a flaw in a fibre channel cable, something I have witnessed), > > then you have two perfectly fine copies of the junk. > > Why do you have just one FC path? We didn't. It just happened that the cable that the data were sent over was buggy. > > I am not saying the (physical) disk is the single point of failure, the > > (logical) file system is (Oracle calls it ASM / tablespace, but it is > > still a file system). > > Why isn't the filesystem (or RDBMS) throwing checksum errors? This was > standard stuff in legacy Enterprise RDBMSs 20 years ago. Checksums are nice for telling you that your storage is screwed. They don't fix the problem. Yours, Laurenz Albe -- Cybertec | https://www.cybertec-postgresql.com
