From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brown Subject: Re: misunderstanding of spare and raid devices? - and one question more Date: Sat, 02 Jul 2011 11:42:02 +0200 Message-ID: References: <4E0C5539.4030000@gmx.de> <4E0C5E47.5090604@anonymous.org.uk> <4E0C6CC4.3030506@turmel.org> <4E0C7196.1070307@gmx.de> <4E0C7B4B.7090404@turmel.org> <4E0C8685.3020806@gmx.de> <4E0C8BD6.1080907@turmel.org> <4E0ED816.30903@gmx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <4E0ED816.30903@gmx.de> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids On 02/07/11 10:34, Karsten R=C3=B6mke wrote: > Hi Phil, > I have done some tests and appended the results, maybe they are of in= terest > for somebody. As a conclusion I would say raid5 and raid6 make in my > situation > nearly no difference. > Thanks to all for hints and explanation > Karsten > If raid6 doesn't have any noticeable performance costs compared to raid= 5=20 for your usage, then you should definitely use raid6 rather than raid5 = +=20 spare. Think of it as raid5 + spare with the rebuild done in advance! mvh., David > > > ---------------------------------------------------------------------= ----------------- > > first - just copy a dir with a size of 2,9 GB, it was copied once bef= ore > so I > think there are still data buffered? > > OLDER war im Cache? hatte Dir vorher kopiert > kspace9:~ # date ; cp -a /home/roemke/HHertzTex/OLDER/* /raid5/ ; dat= e > Fr 1. Jul 16:15:57 CEST 2011 > Fr 1. Jul 16:16:26 CEST 2011 > > kspace9:~ # date ; cp -a /home/roemke/HHertzTex/OLDER/* /raid6/ ; dat= e > Fr 1. Jul 16:17:27 CEST 2011 > Fr 1. Jul 16:17:58 CEST 2011 > > ---------------------------------------------------------------------= ----------------- > > now a test with bonnie, I found this example online and the parameter= s > seems > senseful to me (I've never done performance tests on hd's before, so = I > searched > for an example) > bonnie, found > -n 0 : file creation 0 > -u 0 : root > -r : memory in megabyte (calculated to 7999) > -s : file size calculated to 15998 > -f : fast, skip per char IO-tests > -b : no write buffering > -d : set directory > > kspace9:~ # bonnie++ -n 0 -u 0 -r `free -m | grep 'Mem:' | awk '{prin= t > $2}'` -s $(echo "scale=3D0;`free -m | grep 'Mem:' | awk '{print $2}'`= *2" | > bc -l) -f -b -d /raid5 > Using uid:0, gid:0. > Writing intelligently...done > Rewriting...done > Reading intelligently...done > start 'em...done...done...done... > Version 1.03d ------Sequential Output------ --Sequential Input- --Ran= dom- > -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- > Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %= CP > kspace9 15998M 96365 20 48302 12 149445 18 113.7 0 > kspace9,15998M,,,96365,20,48302,12,,,149445,18,113.7,0,,,,,,,,,,,,, > > kspace9:~ # bonnie++ -n 0 -u 0 -r `free -m | grep 'Mem:' | awk '{prin= t > $2}'` -s $(echo "scale=3D0;`free -m | grep 'Mem:' | awk > '{print $2}'`*2" | bc -l) -f -b -d /raid6 > Using uid:0, gid:0. > Writing intelligently...done > Rewriting...done > Reading intelligently...done > start 'em...done...done...done... > Version 1.03d ------Sequential Output------ --Sequential Input- --Ran= dom- > -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- > Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %= CP > kspace9 15998M 100321 22 48617 13 131651 16 120.2 1 > kspace9,15998M,,,100321,22,48617,13,,,131651,16,120.2,1,,,,,,,,,,,,, > > > =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D > > results for old raid 1: > a test of old raid 1 which I have done unintended, because I forgot t= o > mount > the raid array :-) > mounten vergessen > --------------------------------------------------------------------- > -> vergleichsresultate :-) > > kspace9:~ # date ; cp -r /home/roemke/HHertzTex/OLDER/ /raid5/ ; date > Fr 1. Jul 16:07:32 CEST 2011 ^^^ not raid 5, old raid 1, forgot to mo= unt > Fr 1. Jul 16:08:39 CEST 2011 > aehnlich (similiar) > > > test mit bonnie++ > kspace9:~ # bonnie++ -n 0 -u 0 -r `free -m | grep 'Mem:' | awk '{prin= t > $2}'` -s $(echo "scale=3D0;`free -m | grep 'Mem:' | awk '{print $2}'`= *2" | > bc -l) -f -b -d /raid5 <-- not raid 5, still the older raid 1 > Using uid:0, gid:0. > Writing intelligently...done > Rewriting...done > Reading intelligently...done > start 'em...done...done...done... > Version 1.03d ------Sequential Output------ --Sequential Input- --Ran= dom- > -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks-- > Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %= CP > kspace9 15998M 62977 9 34410 9 101979 13 66.7 0 > kspace9,15998M,,,62977,9,34410,9,,,101979,13,66.7,0,,,,,,,,,,,,, > -- > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html