R: [Voyage-linux] ext3

[Dario Finardi]

I think Jeff's problem is to have both data and filesystem integrity even if the system experience a powerloss.

....Jeff, may you give us some more specifics?

-----Messaggio originale-----
Da: voyage-linux-bounces+d.finardi=gear.it at list.voyage.hk [mailto:voyage-linux-bounces+d.finardi=gear.it at list.voyage.hk] Per conto di Ben Kochie
Inviato: martedì 24 marzo 2009 22.05
A: Jeff R. Allen
Cc: voyage-linux
Oggetto: Re: [Voyage-linux] ext3

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

One option for writing to a flash in a nice pattern would be to use a log filesystem.

http://logfs.org/

- -ben

  "UNIX is user-friendly, it's just picky about its friends."

On Tue, 24 Mar 2009, Jeff R. Allen wrote:

>> I don't bother with ext3 since it drastically reduces the lifetime of 
>> the CF card.  Also, log files and the like are not written to disk so 
>> there is not as much IO as you might think.
>
> Not to be critical, but your response is contradictory and I can't 
> make sense of it. Can you clarify?
>
> Some facts:
>  * under voyage, the root is mounted read-only, which means you can 
> use it on a CF card with no degradation no matter what filesystem you 
> use.
>  * In stock Voyage, files are only written to the CF card when you do 
> the explicit sync operation of the stuff in /rw back to /ro, or when 
> you explicitly remount the root rw and start scribbling on things with 
> your own scripts/servers/etc.
>
> I'm very interested in this right now, because I'm currently 
> contemplating what the right mix is between ramdisk and CF disk when 
> running a mySQL database. I'm currently leaning towards running it in 
> RAM, and flushing to CF card via mysql_copy under app control -- so 
> that the app only flushes the database when it knows there's been a 
> precious write.
>
> I'm an OpenWRT user too, and I'm considering using a jffs2 overlay for 
> my ext2 formatted mysql-dump filesystem, just like OpenWRT does for 
> it's entire filesystem.
>
> Anyone got any suggestions for how to safely do regular writes?
>
>  -jeff
>
> _______________________________________________
> Voyage-linux mailing list
> Voyage-linux at list.voyage.hk
> http://list.voyage.hk/mailman/listinfo/voyage-linux
>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.6 (GNU/Linux)

iD8DBQFJyUrrfYg2asD844oRAvRrAJ9DqRHQK6puIM7PX72GwUiImeasWgCfXR/M
ErYv4LV8Zlf4nqlCb6YWGiw=
=44Zh
-----END PGP SIGNATURE-----