All of lore.kernel.org
 help / color / mirror / Atom feed
From: Dallas Clement <dallas.a.clement@gmail.com>
To: Mark Knecht <markknecht@gmail.com>
Cc: Phil Turmel <philip@turmel.org>, John Stoffel <john@stoffel.org>,
	Linux-RAID <linux-raid@vger.kernel.org>
Subject: Re: best base / worst case RAID 5,6 write speeds
Date: Mon, 14 Dec 2015 14:55:09 -0600	[thread overview]
Message-ID: <CAE9DZURBQxteib=hW6FskuJCJTxZDWhy5kMVy2u1hU5Nkg8Khg@mail.gmail.com> (raw)
In-Reply-To: <CAK2H+edazVORrVovWDeTA8DmqUL+5HRH-AcRwg8KkMas=o+Cog@mail.gmail.com>

On Mon, Dec 14, 2015 at 2:40 PM, Mark Knecht <markknecht@gmail.com> wrote:
>
>
> On Mon, Dec 14, 2015 at 12:14 PM, Dallas Clement
> <dallas.a.clement@gmail.com> wrote:
>>
>> <SNIP>
>>
>> Hi Phil,  I ran blktrace while writing with dd to a RAID 5 device with
>> 12 disks.  My chunk size is 128K.  So I set my block size to 128K *
>> (12-2) = 1280k.   Here is the dd command I ran.
>
> Just curious but for my own knowledge if it's RAID5 why is it 12-2?
>
> - Mark

> Just curious but for my own knowledge if it's RAID5 why is it 12-2?

Shouldn't be.  It should have been 12-1 or writing 1408k.  Boy do I
feel dumb.  Anyhow, when writing this value, no more RMWs.   Yay!

  parent reply	other threads:[~2015-12-14 20:55 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-10  1:34 best base / worst case RAID 5,6 write speeds Dallas Clement
2015-12-10  6:36 ` Alexander Afonyashin
2015-12-10 14:38   ` Dallas Clement
2015-12-10 15:14 ` John Stoffel
2015-12-10 18:40   ` Dallas Clement
     [not found]     ` <CAK2H+ed+fe5Wr0B=h5AzK5_=ougQtW_6cJcUG_S_cg+WfzDb=Q@mail.gmail.com>
2015-12-10 19:26       ` Dallas Clement
2015-12-10 19:33         ` John Stoffel
2015-12-10 22:19           ` Wols Lists
2015-12-10 19:28     ` John Stoffel
2015-12-10 22:23       ` Wols Lists
2015-12-10 20:06 ` Phil Turmel
2015-12-10 20:09   ` Dallas Clement
2015-12-10 20:29     ` Phil Turmel
2015-12-10 21:14       ` Dallas Clement
2015-12-10 21:32         ` Phil Turmel
     [not found]     ` <CAK2H+ednN7dCGzcOt8TxgNdhdDA1mN6Xr5P8vQ+Y=-uRoxRksw@mail.gmail.com>
2015-12-11  0:02       ` Dallas Clement
     [not found]         ` <CAK2H+efF2dM1BsM7kzfTxMdQEHvbWRaVe7zJLTGcPZzafn2M6A@mail.gmail.com>
2015-12-11  0:41           ` Dallas Clement
2015-12-11  1:19             ` Dallas Clement
     [not found]               ` <CAK2H+ec-zMbhxoFyHXLkdM-z-9cYYzNbPFhn19XjTHqrOMDZKQ@mail.gmail.com>
2015-12-11 15:44                 ` Dallas Clement
2015-12-11 16:32                   ` John Stoffel
2015-12-11 16:47                     ` Dallas Clement
2015-12-11 19:34                       ` John Stoffel
2015-12-11 21:24                         ` Dallas Clement
2015-12-11 23:30                           ` Dallas Clement
2015-12-12  0:00                             ` Dallas Clement
2015-12-12  0:38                               ` Phil Turmel
2015-12-12  2:55                                 ` Dallas Clement
2015-12-12  4:47                                   ` Phil Turmel
2015-12-14 20:14                                     ` Dallas Clement
     [not found]                                       ` <CAK2H+edazVORrVovWDeTA8DmqUL+5HRH-AcRwg8KkMas=o+Cog@mail.gmail.com>
2015-12-14 20:55                                         ` Dallas Clement [this message]
     [not found]                                           ` <CAK2H+ed-3Z8SR20t8rpt3Fb48c3X2Jft=qZoiY9emC2nQww1xQ@mail.gmail.com>
2015-12-14 21:20                                             ` Dallas Clement
2015-12-14 22:05                                               ` Dallas Clement
2015-12-14 22:31                                                 ` Tommy Apel
     [not found]                                                 ` <CAK2H+ecMvDLdYLhMtMQbP7Ygw-VohG7LGZ2n7H+LAXQ1waJK3A@mail.gmail.com>
2015-12-14 23:25                                                   ` Dallas Clement
2015-12-15  2:36                                                     ` Dallas Clement
2015-12-15 13:53                                                       ` Phil Turmel
2015-12-15 14:09                                                       ` Robert Kierski
2015-12-15 15:14                                                       ` John Stoffel
2015-12-15 17:30                                                         ` Dallas Clement
2015-12-15 19:22                                                           ` Phil Turmel
2015-12-15 19:44                                                             ` Dallas Clement
2015-12-15 19:52                                                               ` Phil Turmel
2015-12-15 21:54                                                           ` John Stoffel
2015-12-15 23:07                                                             ` Dallas Clement
2015-12-16 15:31                                                               ` Dallas Clement
     [not found]                                                                 ` <CAK2H+eeD2k4yzuvL4uF_qKycp6A=XPe8pVF_J-7Agi8Ze89PPQ@mail.gmail.com>
2015-12-17  5:57                                                                   ` Dallas Clement
2015-12-17 13:41                                                                   ` Phil Turmel
2015-12-17 21:08                                                                     ` Dallas Clement
2015-12-17 22:40                                                                       ` Phil Turmel
2015-12-17 23:28                                                                         ` Dallas Clement
2015-12-18  0:54                                                                           ` Dallas Clement
     [not found]                                                                             ` <CAFx4rwT8xgwZ0OWaLLsZvhMskiwmY54MzHgnnEPaswByeRrXxQ@mail.gmail.com>
2015-12-22  6:15                                                                               ` Doug Dumitru
2015-12-22 14:34                                                                                 ` Robert Kierski
2015-12-22 16:48                                                                                 ` Dallas Clement
2015-12-22 18:33                                                                                   ` Doug Dumitru
2016-01-04 18:56                                                                                     ` Robert Kierski
2016-01-04 19:13                                                                                       ` Doug Dumitru
2016-01-04 19:33                                                                                         ` Robert Kierski
2016-01-04 19:43                                                                                           ` Doug Dumitru
2016-01-15 16:53                                                                                             ` Robert Kierski

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAE9DZURBQxteib=hW6FskuJCJTxZDWhy5kMVy2u1hU5Nkg8Khg@mail.gmail.com' \
    --to=dallas.a.clement@gmail.com \
    --cc=john@stoffel.org \
    --cc=linux-raid@vger.kernel.org \
    --cc=markknecht@gmail.com \
    --cc=philip@turmel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.