"Andrew Gabriel" wrote in message
...
In article ,
"dennis@home" writes:


"Andrew Gabriel" andrew@cucumber wrote in message
...
Journaling file system are so last millenium.
ZFS manages this fines without journaling... :-)

That's because it journals.

They may call it an intent log but it is a journal.

No. A journal keeps filesystem metadata (the data such as
directories and inodes) which is required to ensure the
filesystem remains self-consistent. It doesn't care about
the file contents.

If you want to define it that way, however the veritas system could put the
data into the log if you asked it to.

The ZFS intent log is for POSIX commit
symantics, i.e. when you explicitly flush a file to disk (and
it does care about file contents, and some metadata changes).
ZFS has no need to journal by design, as the filesystem
metadata is never inconsistent on disk at any point in
time (so the journal would always be empty if it had one,
which is why it doesn't have one, nor an fsck command as
there can never be any journal to replay).

The veritas file system we were using also had an intent log so its not
something new.
In fact Sun acquired the source for it when the bought out SVr5 in the
eighties.

There's no veritas file system source in SVR4. (There's no
such thing as SVR5 -- it was a SCO marketing term only
which came from their doomed project to merge SVR4 and HP-UX.)

Your unix knowledge is a bit lacking.
SVr5 predates SCO by a good margin.
And I know there was veritas source code in it as I had the source code.
In fact I worked with the engineers to customise SVr5 to do what we needed
as well as designing some STREAMs modules to do pseudo real time stuff.
I think you will find it was univel (sp?) hat was spun off from AT&T that
developed SVr5.
One of the main things they did was to compartmentalize the kernel so it
could get B2 (IIRC) security.

BTW all the System X exchanges have Veritas file systems running on some of
the hardware, I put it there.

AIX's filesystem and volume management was developed for
them by veritas, and that probably has internal similarities
with veritas's, but isn't part of the SVR4 sources, and Sun
don't have it. The main SVR4 filesystem, ufs, is derived
from the Berkely Fast Filesystem, via SunOS 4, which AT&T
paid Sun to port into SVR4 (as part of the SunOS 4 memory
management system port to SRV4 which AT&T commissioned Sun
to do). There was no journaling in SVR4 when Sun and AT&T
finished producing it, and Solaris split off. Sun added
journaling to Solaris around 1994 as part of the Disksuite
add-on, and moved the journaling into base Solaris starting
with Solaris 7 (1998?). If journaling appeared in SVR4 source,
it would have been done by AT&T, Novell, or SCO at some later
date. SVR3 and earlier SysV unixes used the System V filesystem
as the default filesystem. (Most vendors created their own variants
of the System V filesystem towards the end of SVR3, as the basic
one had a number of increasingly unacceptable restrictions, such
as 32k or 64k max number of files (or rather inodes), fairly
small max filesize by today's standards, small max filesystem
size, no symlinks, etc.)

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]