Re: file system journaling (was: Re: i-ram vs. tmpfs

[Seth Mattinen <sethm@rollernet.us>]

Roman Pertl wrote:
> On [Fri, 13.04.2007 12:06], Anders Breindahl wrote:
> AB> On 200704101607, Michael Loftis wrote:
> AB> > RAID-5 is extremely slow at writes.  Also can't forget about seeks. 
> AB> > Depending on your access patterns an external journal can be a definite 
> AB> > win, sometimes it's always a win with certain access patterns.  EXT3 also 
> AB> > by default only journals metadata, not data, which means the write rate to 
> AB> > the journal is relatively low.
> AB> 
> AB> Allow me to correct:
> AB> 
> AB> Ext3 journals both data and metadata. Xfs only journals metadata. But
> AB> that might be a relevant issue here, too, as many seem to prefer xfs on
> AB> their mail servers.
>
> no, that's not correct. ext3 can do both, jounral only metadata or
> metadata+data, although i don't know what's the default.

Default is "ordered" mode.

> journal_data_ordered
>         When the filesystem is mounted with journalling enabled, all data is forced directly out to the main
>         file system prior to its metadata being committed to the journal.


--
sethm@rollernet.us
Ne cede malis sed contra audentior ito