From: David Brown <david.brown@hesbynett.no>
To: Andrea Mazzoleni <amadvance@gmail.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>,
linux-raid@vger.kernel.org, linux-btrfs@vger.kernel.org,
David Smith <creamyfish@gmail.com>
Subject: Re: Triple parity and beyond
Date: Thu, 21 Nov 2013 09:36:56 +0100 [thread overview]
Message-ID: <528DC628.9090403@hesbynett.no> (raw)
In-Reply-To: <CAGKKSfV+TyONu0EgSy9r5k7SiP5ZM3n7pGajY62DBSBw6YvR+w@mail.gmail.com>
On 20/11/13 19:34, Andrea Mazzoleni wrote:
> Hi David,
>
>>> The choice of ZFS to use powers of 4 was likely not optimal,
>>> because to multiply by 4, it has to do two multiplications by 2.
>> I can agree with that. I didn't copy ZFS's choice here
> David, it was not my intention to suggest that you copied from ZFS.
> Sorry to have expressed myself badly. I just mentioned ZFS because it's
> an implementation that I know uses powers of 4 to generate triple
> parity, and I saw in the code that it's implemented with two multiplication
> by 2.
>
Andrea, I didn't take your comment as an accusation of any kind - there
is no need for any kind of apology! It was was merely a statement of
fact - I picked powers of 4 as an obvious extension of the powers of 2
in raid6, and found it worked well.
And of course, in the open source world, copying of code and ideas is a
good thing - there is no point in re-inventing the wheel unless we can
invent a better one. Really, I /should/ have read the ZFS
implementation and copied it!
mvh.,
David
next prev parent reply other threads:[~2013-11-21 8:36 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-18 22:08 Triple parity and beyond Andrea Mazzoleni
2013-11-18 22:12 ` H. Peter Anvin
2013-11-18 22:35 ` Andrea Mazzoleni
2013-11-18 23:25 ` H. Peter Anvin
2013-11-19 10:16 ` David Brown
2013-11-19 17:36 ` Andrea Mazzoleni
2013-11-19 22:51 ` Drew
2013-11-20 0:54 ` Chris Murphy
2013-11-20 1:23 ` John Williams
2013-11-20 10:35 ` David Brown
2013-11-20 10:31 ` David Brown
2013-11-20 18:09 ` John Williams
2013-11-20 18:44 ` Andrea Mazzoleni
2013-11-21 6:15 ` Stan Hoeppner
2013-11-21 8:32 ` David Brown
2013-11-20 18:34 ` Andrea Mazzoleni
2013-11-20 18:43 ` H. Peter Anvin
2013-11-20 18:56 ` Andrea Mazzoleni
2013-11-20 18:59 ` H. Peter Anvin
2013-11-20 21:21 ` Andrea Mazzoleni
2013-11-20 19:00 ` H. Peter Anvin
2013-11-20 21:04 ` Andrea Mazzoleni
2013-11-20 21:06 ` H. Peter Anvin
2013-11-21 8:36 ` David Brown [this message]
2013-11-19 17:28 ` Andrea Mazzoleni
2013-11-19 20:29 ` Ric Wheeler
2013-11-20 16:16 ` James Plank
2013-11-20 19:05 ` Andrea Mazzoleni
2013-11-20 19:10 ` H. Peter Anvin
2013-11-20 20:30 ` James Plank
2013-11-20 21:23 ` Andrea Mazzoleni
2013-11-27 2:50 ` ronnie sahlberg
2013-11-20 21:28 ` H. Peter Anvin
2013-11-21 1:28 ` Stan Hoeppner
2013-11-21 2:46 ` John Williams
2013-11-21 6:52 ` Stan Hoeppner
2013-11-21 7:05 ` John Williams
2013-11-21 22:57 ` Stan Hoeppner
2013-11-21 23:38 ` John Williams
2013-11-22 9:35 ` Stan Hoeppner
2013-11-22 11:24 ` joystick
2013-11-22 15:01 ` John Williams
2013-11-22 22:28 ` Stan Hoeppner
2013-11-22 23:07 ` NeilBrown
2013-11-23 3:46 ` Stan Hoeppner
2013-11-23 5:04 ` NeilBrown
2013-11-23 5:34 ` John Williams
2013-11-23 7:12 ` NeilBrown
2013-11-24 4:03 ` Stan Hoeppner
2013-11-24 5:14 ` John Williams
2013-11-24 21:13 ` Stan Hoeppner
2013-11-24 23:28 ` Rudy Zijlstra
2013-11-24 23:53 ` Alex Elsayed
2013-11-25 2:04 ` Stan Hoeppner
2013-11-25 4:48 ` Alex Elsayed
2013-11-25 9:15 ` David Brown
2013-11-24 5:19 ` Russell Coker
2013-11-24 21:44 ` Stan Hoeppner
2013-11-24 22:31 ` Mark Knecht
2013-11-25 2:14 ` Russell Coker
2013-11-25 9:20 ` David Brown
2013-11-21 8:08 ` joystick
2013-11-22 0:30 ` Stan Hoeppner
2013-11-22 0:33 ` H. Peter Anvin
2013-11-22 0:45 ` David Brown
2013-11-21 9:07 ` David Brown
2013-11-21 9:54 ` Adam Goryachev
2013-11-21 10:32 ` David Brown
2013-11-22 8:12 ` Russell Coker
2013-11-25 18:23 ` Pasi Kärkkäinen
2013-11-22 8:13 ` Stan Hoeppner
2013-11-22 13:15 ` David Brown
2013-11-22 16:07 ` Stan Hoeppner
2013-11-22 22:59 ` NeilBrown
2013-11-23 17:39 ` David Brown
2013-11-22 16:50 ` Mark Knecht
2013-11-22 19:51 ` Duncan
2013-11-22 8:38 ` Stan Hoeppner
2013-11-22 13:24 ` David Brown
2013-11-28 7:16 ` Stan Hoeppner
2013-11-28 7:36 ` Russell Coker
2013-11-28 9:56 ` David Brown
2013-11-30 7:32 ` Alex Elsayed
2013-12-01 15:37 ` Stan Hoeppner
2013-11-22 14:19 ` David Taylor
2013-11-21 19:56 ` Piergiorgio Sartor
2013-11-19 18:12 ` Piergiorgio Sartor
2013-11-20 10:44 ` David Brown
2013-11-20 21:59 ` Piergiorgio Sartor
2013-11-21 10:13 ` David Brown
2013-11-21 17:37 ` Goffredo Baroncelli
2013-11-21 20:05 ` Piergiorgio Sartor
2013-11-21 20:31 ` David Brown
2013-11-21 20:52 ` Piergiorgio Sartor
2013-11-22 0:32 ` David Brown
2013-11-22 20:32 ` Piergiorgio Sartor
2013-11-26 18:10 ` joystick
2013-11-20 21:38 ` Andrea Mazzoleni
2013-11-20 22:29 ` Piergiorgio Sartor
2013-11-23 7:55 ` Andrea Mazzoleni
2013-11-23 22:10 ` Piergiorgio Sartor
2013-11-24 9:39 ` Andrea Mazzoleni
-- strict thread matches above, loose matches on Subject: below --
2013-12-01 17:53 Richard Scobie
2013-12-02 4:30 ` Stan Hoeppner
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