lkml.org 
[lkml]   [1998]   [Dec]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: Should raw I/O be added to the kernel?
Linus Torvalds <torvalds@transmeta.com> writes:
>The only argument for raw disk IO is the caching policy issue

Exactly right. Without raw disk IO, you couldn't guarantee a database
to always be in a consistent state on the disk (i.e. it isn't very
desirable to have a committed transaction in a cache when the pc loses
power). It makes it impossible to recover the database. And what
good is having a transaction oriented database on Linux in a
production environment if you can't be guaranteed to recover it after
a crash?

From my days at Unify a decade ago, you had to use raw disk IO because
fsync() wasn't guaranteed to have flushed the cache completely to the
disk before it returned. Of course, I'll be the first to admit that I
haven't checked out the kernel source to see if this is true for
Linux. But, I'm sure that someone will so that the database part of
this thread can be put to rest.

--
Forte International, P.O. Box 1412, Ridgecrest, CA 93556-1412
Ronald Cole <ronald@forte-intl.com> Phone: (760) 499-9142
President, CEO Fax: (760) 499-9152
My PGP fingerprint: 15 6E C7 91 5F AF 17 C4 24 93 CB 6B EB 38 B5 E5

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:46    [W:0.079 / U:0.100 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site