raveling@vaxb.isi.edu (Paul Raveling) (03/10/89)
Some of the recent discussion on UNIX pros & cons dealt with file systems. Appended below is a related message from comp.sys.hp and comp.databases that I've taken the liberty to forward. The bottom line is that DBMS people need more than UNIX offers and it's costing a lot for them and sometimes for their users. ---------------- Paul Raveling Raveling@isi.edu In article <28308@ucbvax.BERKELEY.EDU> jas@ernie.Berkeley.EDU.UUCP (Jim Shankland) writes: >In article <735@hscfvax.harvard.edu> pavlov@hscfvax.harvard.edu (G.Pavlov) writes: >>In article <115@geysir.os.is>, eik@os.is (Einar Kjartansson) writes: >[about how Oracle has repeatedly soiled its filesystem on an HP 9000/840, >causing loss of several days' work each time ...] > >> I fail to understand how anyone can seriously consider purchasing a DBMS >> that insists on "improving" performance by bypassing a given system's file >> management facility. It's a cheap method for the vendor, but as the above >> has discovered, may be very expensive to the user.... The user is >> now faced with a big black box (a large extent of disk >> space known only as a huge "file" to the system) which is difficult to pene- >> trate with the usual system debugging tools and has to be overwritten in >> toto from backup. > >There are some persuasive reasons for rolling your own filesystem when >you're implementing a DBMS, especially on UNIX, whose filesystem serves >DBMS implementors poorly. The problem is not just speed, but reliability. >Ideally, you'd like the UNIX vendors to provide reasonable file system >services; but if they don't, you're stuck with either using the miserable >services they provide, or rolling your own. > >Of course, if you do roll your own, you need to do the whole job. That >means being damned sure it's robust and correct, *and* providing >filesystem debugging, repair, and analysis tools. Doing the job >right is by no means "a cheap method for the vendor." > >Jim Shankland >jas@ernie.berkeley.edu > >"There is no help, for all these things are so, > And all the world is bitter as a tear."