Very low disk performance on 5.x

[Arne Wörner]

--- Arne Wörner <arne_woerner at yahoo.com> wrote:
> --- Petri Helenius <pete at he.iki.fi> wrote:
> > Eric Anderson wrote:
> > I'm seeing similar sequential performance on RELENG_5_3
> > and RELENG_5_4 on dual-Xeons using 3ware controllers so
> > it does not seem to be a driver issue [...]
> >
> Why?
> 
I found something out:
1. read and write speeds (same partition; hw.ata.wc=1;
   dd bs=128k count=2000; 512MB RAM):
       R4.11    R5.3
    R  27.5MB/s 27.5MB/s
    W  27MB/s   5.15MB/s
2. The man page geom(4) does not exist in R4.11
3. The man page geom(4) of R5.3 says "The GEOM framework
   provides an infrastructure in which "classes" can per-
   form transformations on disk I/O requests on their path
   from the upper kernel to the device drivers and back.

Could it be, that geom slows something down (in some boxes the
reading ops are very slow; in my box the writing ops are very
slow)?

-Arne


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