On Mon, Nov 29, 1999 at 02:58:42AM -0500, Remo Strotkamp wrote:
> Hi there,
>
> first of all thanx for all the replies concerning my previous mail.
> second: hi jakob and here are the single mode bonnie results...
Thanks :)
> I have done some basic benchmarking in single user mode, and got strange
> results:
>
> First of all the setup:
> I have a raid-1 partition of 64MB over all 8 disks, as well as a raid-5
> over 5 disks a 19GB each.
> Now as I have 128MB of RAM, I used the mem=16m for reducing the amount
> of memory to get
> reasonable results for my raid-1.
If you use a filesize large enough, (like 200-500 megs) you can safely run
with the 128 megs enabled. I'm not sure how mem=16m will affect the
performance.
> Here they are:
...
> Then I ran bonnie two times with the full amount of memory:
>
>
> -------Sequential Output-------- ---Sequential Input-- --Random--
> -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
> Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
> 2047 7184 90.2 28856 23.2 17191 32.5 8301 97.5 60630 43.0 201.1 3.7
>
>
> -------Sequential Output-------- ---Sequential Input-- --Random--
> -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
> Machine MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
> 2047 7183 90.2 29521 24.1 17086 31.7 8305 97.5 60009 43.3 201.6 2.8
That's more like it! :)
> I also used hdparm -t and the raid1 achieves 32MB/s while raid5 achieves
> 55MB!!!
>
>
> I am really confused by those results, especially by the reading
> performance.
> There are 8 disks in the raid1 and only 5 in the raid5, so I would
> expect the raid1 beeing lots faster,
> as reads are spread in parallel over lots more of disks!!!!!! But it
> seems to be alot slower....
Contrary to what the HOWTO says (ouch!) RAID-1 doesn't (yet) distribute
reads over the disks. RAID-5 does (has to).
Mika Kuoppala is working on a patch that makes RAID-1 distribute reads over the
disks. Hopefully in the not-too-distant future, you will see better
performance from RAID-1 in many cases.
It's pretty hard to make RAID-1 run faster in a bonnie test, as bonnie works
with one file only. But in a production environment, many files are usually
accessed simultaneously, and it should be possible for RAID-1 to scale there.
--
................................................................
: [EMAIL PROTECTED] : And I see the elder races, :
:.........................: putrid forms of man :
: Jakob Østergaard : See him rise and claim the earth, :
: OZ9ABN : his downfall is at hand. :
:.........................:............{Konkhra}...............:
