On 9/25/2014 3:43 PM, Dimitry Sibiryakov wrote: > 25.09.2014 21:27, Leyne, Sean wrote: >> Installing on physical server means that you have a single point of failure. > Modern storage systems claim that they have no single point of failure, > BTW. Some of > them even allows two or more servers to be attached. > But all this is pointless because Firebird server itself is a SPoF. > Actually, not. Interbase like Rdb/ELN was written to run on VaxClusters, which is why the Interbase lock manager was semantically identical to the VMS Distributed Lock Manager. With careful write and shadowed file systems, it had no single point of failure.
This, incidentally, is the architecture that Oracle later adopted for RAC. And, like the early version of RAC, it suffered from heavy update loads where processor A wanting a dirty page from processor B had to wait for B to write the page, release the lock, then read the page from disk. Oracle addressed the problem with fast network connections between nodes to pass "dirty" pages directly without having to wait for the disk to write then re-read the block. Given a suitable distributed lock manger (!) and forced write, Firebird could run without a single point of failure, assuming the hardware was all done write. Personally, I don't think it's worth the effort and that there are a class of much more interesting architectures to completely isolate the SQL engines from disk. NuoDB, for example, has transaction nodes that are essentially diskless (meaning the database engine never opens a disk file, not that the OS works sans disk). ------------------------------------------------------------------------------ Meet PCI DSS 3.0 Compliance Requirements with EventLog Analyzer Achieve PCI DSS 3.0 Compliant Status with Out-of-the-box PCI DSS Reports Are you Audit-Ready for PCI DSS 3.0 Compliance? Download White paper Comply to PCI DSS 3.0 Requirement 10 and 11.5 with EventLog Analyzer http://pubads.g.doubleclick.net/gampad/clk?id=154622311&iu=/4140/ostg.clktrk Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
