From: kedacomkernel <kedacomkernel@gmail.com>
To: Andy Lutomirski <luto@amacapital.net>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-raid <linux-raid@vger.kernel.org>
Subject: Re: O_DIRECT to md raid 6 is slow
Date: Wed, 15 Aug 2012 09:07:06 +0800 [thread overview]
Message-ID: <201208150906343285670@gmail.com> (raw)
In-Reply-To: CALCETrWCu=UPATPdqWP=Gpvswv-RDwaxfr1W1jxYtUMZsqKgSQ@mail.gmail.com
On 2012-08-15 08:49 Andy Lutomirski <luto@amacapital.net> Wrote:
>If I do:
># dd if=/dev/zero of=/dev/md0p1 bs=8M
>then iostat -m 5 says:
>
>avg-cpu: %user %nice %system %iowait %steal %idle
> 0.00 0.00 26.88 35.27 0.00 37.85
>
>Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
>sdb 265.20 1.16 54.79 5 273
>sdc 266.20 1.47 54.73 7 273
>sdd 264.20 1.38 54.54 6 272
>sdf 286.00 1.84 54.74 9 273
>sde 266.60 1.04 54.75 5 273
>sdg 265.00 1.02 54.74 5 273
>md0 55808.00 0.00 218.00 0 1090
>
>If I do:
># dd if=/dev/zero of=/dev/md0p1 bs=8M oflag=direct
>then iostat -m 5 says:
>avg-cpu: %user %nice %system %iowait %steal %idle
> 0.00 0.00 11.70 12.94 0.00 75.36
>
>Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
>sdb 831.00 8.58 30.42 42 152
>sdc 832.80 8.05 29.99 40 149
>sdd 832.00 9.10 29.78 45 148
>sdf 838.40 9.11 29.72 45 148
>sde 828.80 7.91 29.79 39 148
>sdg 850.80 8.00 30.18 40 150
>md0 1012.60 0.00 101.27 0 506
>
>It looks like md isn't recognizing that I'm writing whole stripes when
>I'm in O_DIRECT mode.
>
kernel version?
>--Andy
>
>--
>Andy Lutomirski
>AMA Capital Management, LLC
>--
>To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at http://vger.kernel.org/majordomo-info.html
WARNING: multiple messages have this Message-ID (diff)
From: kedacomkernel <kedacomkernel@gmail.com>
To: "Andy Lutomirski" <luto@amacapital.net>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-raid <linux-raid@vger.kernel.org>
Subject: Re: O_DIRECT to md raid 6 is slow
Date: Wed, 15 Aug 2012 09:07:06 +0800 [thread overview]
Message-ID: <201208150906343285670@gmail.com> (raw)
In-Reply-To: CALCETrWCu=UPATPdqWP=Gpvswv-RDwaxfr1W1jxYtUMZsqKgSQ@mail.gmail.com
[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset="gb2312", Size: 2146 bytes --]
On 2012-08-15 08:49 Andy Lutomirski <luto@amacapital.net> Wrote:
>If I do:
># dd if=/dev/zero of=/dev/md0p1 bs=8M
>then iostat -m 5 says:
>
>avg-cpu: %user %nice %system %iowait %steal %idle
> 0.00 0.00 26.88 35.27 0.00 37.85
>
>Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
>sdb 265.20 1.16 54.79 5 273
>sdc 266.20 1.47 54.73 7 273
>sdd 264.20 1.38 54.54 6 272
>sdf 286.00 1.84 54.74 9 273
>sde 266.60 1.04 54.75 5 273
>sdg 265.00 1.02 54.74 5 273
>md0 55808.00 0.00 218.00 0 1090
>
>If I do:
># dd if=/dev/zero of=/dev/md0p1 bs=8M oflag=direct
>then iostat -m 5 says:
>avg-cpu: %user %nice %system %iowait %steal %idle
> 0.00 0.00 11.70 12.94 0.00 75.36
>
>Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
>sdb 831.00 8.58 30.42 42 152
>sdc 832.80 8.05 29.99 40 149
>sdd 832.00 9.10 29.78 45 148
>sdf 838.40 9.11 29.72 45 148
>sde 828.80 7.91 29.79 39 148
>sdg 850.80 8.00 30.18 40 150
>md0 1012.60 0.00 101.27 0 506
>
>It looks like md isn't recognizing that I'm writing whole stripes when
>I'm in O_DIRECT mode.
>
kernel version?
>--Andy
>
>--
>Andy Lutomirski
>AMA Capital Management, LLC
>--
>To unsubscribe from this list: send the line "unsubscribe linux-raid" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at http://vger.kernel.org/majordomo-info.htmlÿôèº{.nÇ+‰·Ÿ®‰†+%ŠËÿ±éݶ\x17¥Šwÿº{.nÇ+‰·¥Š{±þG«éÿŠ{ayº\x1dʇڙë,j\a¢f£¢·hšïêÿ‘êçz_è®\x03(階ŠÝ¢j"ú\x1a¶^[m§ÿÿ¾\a«þG«éÿ¢¸?™¨èÚ&£ø§~á¶iO•æ¬z·švØ^\x14\x04\x1a¶^[m§ÿÿÃ\fÿ¶ìÿ¢¸?–I¥
next prev parent reply other threads:[~2012-08-15 1:07 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-15 0:49 O_DIRECT to md raid 6 is slow Andy Lutomirski
2012-08-15 1:07 ` kedacomkernel [this message]
2012-08-15 1:07 ` kedacomkernel
2012-08-15 1:12 ` Andy Lutomirski
2012-08-15 1:23 ` kedacomkernel
2012-08-15 1:23 ` kedacomkernel
2012-08-15 11:50 ` John Robinson
2012-08-15 17:57 ` Andy Lutomirski
2012-08-15 22:00 ` Stan Hoeppner
2012-08-15 22:10 ` Andy Lutomirski
2012-08-15 23:50 ` Stan Hoeppner
2012-08-16 1:08 ` Andy Lutomirski
2012-08-16 6:41 ` Roman Mamedov
2012-08-15 23:07 ` Miquel van Smoorenburg
2012-08-16 11:05 ` Stan Hoeppner
2012-08-16 21:50 ` Miquel van Smoorenburg
2012-08-17 7:31 ` Stan Hoeppner
2012-08-17 11:16 ` Miquel van Smoorenburg
2012-08-18 5:09 ` Stan Hoeppner
2012-08-18 10:08 ` Michael Tokarev
2012-08-19 3:17 ` Stan Hoeppner
2012-08-19 14:01 ` David Brown
2012-08-19 23:34 ` Stan Hoeppner
2012-08-20 0:01 ` NeilBrown
2012-08-20 4:44 ` Stan Hoeppner
2012-08-20 5:19 ` Dave Chinner
2012-08-20 5:42 ` Stan Hoeppner
2012-08-20 7:47 ` David Brown
2012-08-21 14:51 ` Miquel van Smoorenburg
2012-08-22 3:59 ` Stan Hoeppner
2012-08-19 17:02 ` Chris Murphy
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