Re: Is Unix security really so weak?

[bringing in comp.databases.oracle.server]

This started as a security discussion, but the quoted poster has been asserting that use of raw devices was somehow essential for Oracle for data to be recoverable.

>>>>> "Nick" == Nick Maclaren <nmm1_at_cus.cam.ac.uk> writes:

 Nick> I suggest that you learn a little more about the combination of Unix,
 Nick> Oracle, dumping while the system is running, and data recovery.  Yes,
 Nick> it will work just fine until there is a crash while it is updating its
 Nick> data - so you shouldn't have a problem, having no data :-)
 

>> Uh, what do you think that redo logs, fsync(), online backup etc. are all
>> for?

 Nick> I suggest that you look into them a little more closely; especially
 Nick> the conditions that Oracle needs for its recovery to be reliable, and
 Nick> what Unix file systems ACTUALLY do.

I know quite a lot about what Unix file systems actually do, thank you. I do not have access to much Oracle information at present (haven't touched it since leaving my last job earlier this year), but I can quite categorically say that your statements are not backed up by those Oracle manuals that I have read. Since you presumably have the information to hand, and I don't, perhaps you could detail precisely what conditions you think are applicable?

 Nick> A clue:  I have used several Unix filesystems where (a) fsync was not
 Nick> available or (b) where it was available but purely decorative.  In both
 Nick> cases, later writes could overtake earlier ones (intervening fsync or
 Nick> even close notwithstanding).  This is more common than you think.

I am quite aware of that. I am also aware that in the platform-specific Oracle documentation for one such system (SCO 3.2v4) there is not the slightest hint that using raw devices is anything more than a performance issue.

Perhaps you (or someone from the Oracle group) could provide some actual information rather that unsupported statements?

-- 
Andrew.

comp.unix.programmer FAQ: see <URL: http://www.erlenstar.demon.co.uk/unix/>