linux-kernel - Re: [ANNOUNCE] Ramback: faster than a speeding bullet

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 17 Mar 2008 07:42:59 -0700 (PDT)
From:	david@...g.hm
To:	Daniel Phillips <phillips@...nq.net>
cc:	David Newall <davidn@...idnewall.com>,
	Alan Cox <alan@...rguk.ukuu.org.uk>, Willy Tarreau <w@....eu>,
	linux-kernel@...r.kernel.org
Subject: Re: [ANNOUNCE] Ramback: faster than a speeding bullet

On Mon, 17 Mar 2008, Daniel Phillips wrote:

> On Sunday 16 March 2008 23:49, david@...g.hm 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 never out of date.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.

your network will do less then 1 Gbit/sec, so to mirror in real-time (what 
you claim is trivial) you would need at least 24 network connections in 
parallel. that's a LOT harder to setup then a high performance disk array.

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