Re: [ANNOUNCE] Ramback: faster than a speeding bullet

From: Daniel Phillips
Date: Mon Mar 17 2008 - 04:16:57 EST


On Sunday 16 March 2008 23:49, david@xxxxxxx wrote:
> > Mirroring on the other hand, makes a realtime copy of a volume, that is
> > never out of date.
>
> so just mirror to a local disk array then.

Great idea. Except that the disk array has millisecond level latency,
when what we trying to achieve is microsecond level latency.

> a local disk array has more write bandwidth than a network connection to a
> remote machine, so if you can mirror to a remote machine you can mirror to
> a local disk array.

So you could potentially connect to a _huge_ disk array and write deltas
to it. The disk array would have to support roughly 3 Gbytes/second of
write bandwidth to keep up with the Violin ramdisk. Doable, but you are
now in the serious heavy iron zone.

Personally, I like my nice simple design a lot more. Just mirror it, as
many times as you need to satisfy your paranoia. Or how about go write
your own?

Daniel
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/