Re: Opinions XFS

[bob@proulx.com (Bob Proulx)]

Mumia W.. wrote:
> David Brodbeck wrote:
> > However, it doesn't journal data, only metadata, so you may lose a
> > bit of data if the system goes down uncleanly.  The filesystem
> > will be protected from corruption, however.  (Ext3fs can also be
> > configured this way, but its default is to journal data as well as
> > metadata.)
>
> It was my understanding that, by default, ext3 only journals metadata. 
> You have to use one of the "journal_data*" options specified in "man 
> tune2fs" to get ext3 to journal data.

This is a change between the way that it used to be and the way that
it is now.  See this FAQ:

  http://batleth.sapienti-sat.org/projects/FAQs/ext3-faq.html

  "mount -o data=journal"
        Journals all data and metadata, so data is written twice. This
        is the mode which all prior versions of ext3 used.

  "mount -o data=ordered"
        Only journals metadata changes, but data updates are flushed to
        disk before any transactions commit. Data writes are not atomic
        but this mode still guarantees that after a crash, files will
        never contain stale data blocks from old files.

  The default data mode is Journaled for a V1 journal, and Ordered for V2.

Bob