[Soekris] freebsd 8.3 on net5501 booting from CF questions

Michael Proto mike at jellydonut.org
Thu Jun 7 14:57:48 UTC 2012


On Wed, Jun 6, 2012 at 9:18 PM, Michael Sierchio <kudzu at tenebras.com> wrote:
> On Wed, Jun 6, 2012 at 6:05 PM, Philip <subs at christiantena.net> wrote:
>
>> /dev/ad0s1a on / (ufs, local, noatime)
>> devfs on /dev (devfs, local, multilabel)
>> /dev/ad1s1d on /var (ufs, local, soft-updates)
>> /dev/ad1s1e on /data (ufs, local, soft-updates)
>
>> I didn't ask for "soft-updates"; it seems to be the default.  Is it
>> good/bad/doesn't matter on something like a net5501 ?  Reliability and
>> crash recovery are more important to me than performance.
>
> Softupdates is designed to maintain disk integrity in event of a crash
> or power outage.  It tracks and enforces metadata dependencies.
>
> No filesystem can guarantee against all data loss, but softupdates
> maintains filesystem consistency.
>
> I would not use softupdates for a stable queue - it destroys atomicity
> of link/unlink operations, for example (though it is possible to force
> data/metadata writes after link operations by opening the directory
> itself rw, then immediately closing it, according to private
> communication from Kirk McKusick).
>
> I think that, for your purposes, it's the right choice.
>
> - M


If you want true reliability you might want to use the "sync" mount
option. This performs all IO to the disk synchronously. It does come
with a performance penalty in IO but if you're more interested in
reliability over disk write speeds (particularly for /, which
shouldn't see very many writes anyway) you might want to look into it.


-Proto


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