Subject: Re: Which file-system is good for power down?
To: None <cliff@snipe444.org>
From: Aleksey Cheusov <cheusov@tut.by>
List: netbsd-users
Date: 12/29/2007 14:00:03
> Note that ext3 only journals the meta data,
This is not true. Ext3 can also write data to the journal.
mount(1):
...
Mount options for ext3
data=journal / data=ordered / data=writeback
Specifies the journalling mode for file data. Metadata is always
jour- naled. To use modes other than ordered on the root file
system, pass the mode to the kernel as boot parameter, e.g.
rootflags=data=journal.
journal
All data is committed into the journal prior to being written into
the main file system.
ordered
This is the default mode. All data is forced directly out to the
main file system prior to its metadata being committed to the
journal.
writeback
Data ordering is not preserved - data may be written into the main
file system after its metadata has been committed to the journal.
This is rumoured to be the highest-throughput option. It guaran-
tees internal file system integrity, however it can allow old data
to appear in files after a crash and journal recovery.
--
Best regards, Aleksey Cheusov.