gpart -b 34 versus gpart -b 1024

[Dan Langille]

On 7/24/2010 10:44 PM, Dan Langille wrote:
> You may have seen my cunning plan:
> http://docs.freebsd.org/cgi/getmsg.cgi?fetch=883310+0+current/freebsd-stable
>
>
> I've been doing some testing today. The first of my tests comparing
> partitions aligned on a 4KB boundary are in. I created a 5x2TB zpool,
> each of which was set up like this:
>
> gpart add -b 1024 -s 3906824301 -t freebsd-zfs -l disk01 ada1
> or
> gpart add -b 34 -s 3906824301 -t freebsd-zfs -l disk01 ada1
>
> Repeat for all 5 HDD. And then:
>
> zpool create storage raidz2 gpt/disk01 gpt/disk02 gpt/disk03 gpt/disk04
> gpt/disk05
>
> Two Bonnie-64 tests:
>
> First, with -b 34:
>
> # ~dan/bonnie-64-read-only/Bonnie -s 5000
> File './Bonnie.12315', size: 5242880000
> Writing with putc()...done
> Rewriting...done
> Writing intelligently...done
> Reading with getc()...done
> Reading intelligently...done
> Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done...
> -------Sequential Output-------- ---Sequential Input-- --Random--
> -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
> GB M/sec %CPU M/sec %CPU M/sec %CPU M/sec %CPU M/sec %CPU /sec %CPU
> 5 110.6 80.5 115.3 15.1 60.9 8.5 68.8 46.2 326.7 15.3 469 1.4
>
>
>
>
> And then with -b 1024
>
> # ~dan/bonnie-64-read-only/Bonnie -s 5000
> File './Bonnie.21095', size: 5242880000
> Writing with putc()...done
> Rewriting...^[[1~done
> Writing intelligently...done
> Reading with getc()...done
> Reading intelligently...done
> Seeker 1...Seeker 2...Seeker 3...start 'em...done...done...done...
> -------Sequential Output-------- ---Sequential Input-- --Random--
> -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
> GB M/sec %CPU M/sec %CPU M/sec %CPU M/sec %CPU M/sec %CPU /sec %CPU
> 5 130.9 94.2 118.3 15.6 61.1 8.5 70.1 46.8 241.2 12.7 473 1.4
>
>
> My reading of this: All M/sec rates are faster except sequential input.
> Comments?
>
> I'll run -s 20000 and -s 50000 tests overnight and will post them in the
> morning.

Well, it seems I'm not sleeping yet, so:

-b 34

        -------Sequential Output-------- ---Sequential Input-- --Random--
        -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
     GB M/sec %CPU M/sec %CPU M/sec %CPU M/sec %CPU M/sec %CPU  /sec %CPU
     50 113.1 82.4 114.6 15.2  63.4  8.9  72.7 48.2 142.2  9.5   126  0.7


-b 1024
        -------Sequential Output-------- ---Sequential Input-- --Random--
        -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
     GB M/sec %CPU M/sec %CPU M/sec %CPU M/sec %CPU M/sec %CPU  /sec %CPU
     50 110.5 81.0 112.8 15.0  62.8  9.0  72.9 48.5 139.7  9.5   144  0.9

Here, the results aren't much better either...  am I not aligning this 
partition correctly?  Missing something else?  Or... are they both 4K 
block aligned?

-- 
Dan Langille - http://langille.org/