geom_stripe and Performance

[Drew Tomlinson]

When using FBSD 4.x, I used vinum to stripe my /usr across two drives.  
Performance seemed good but I never used any tools to actually measure 
it.  Now I've upgraded to 5.4 (and will upgrade to 6.0 soon) and disk 
performance doesn't seem very good.  When upgrading to 5.4, I ditched 
vinum in favor of geom_stripe as that seemed to be the way to go from my 
reading on the lists.

My box is a small personal server I use in my home.  It provides mail 
services, personal web space, etc but is not heavily used.  The box has 
two 9GB SCSI drives in it.  I set it up with a 500 MB root partition on 
one drive, 500 MB swap on the other, and then built the /usr stripe with 
the remaining space on both drives.  Other partitions such are /var, 
/tmp, /home, etc. are symlinked to /usr/var, /usr/tmp, /usr/home, etc. 
as described in The Complete FreeBSD 3rd edition.

When I created the vinum stripes, I followed instructions in the vinum 
man pages and docs at http://vinum.org.  As I recall, those docs 
suggested a large stripe size that was not a power of 2 to reduce 
seeking.  'man tuning' also recommends a large stripe under the 
"STRIPING DISKS" section and suggests a stripe size of 1152 blocks.

However when I created the geom_stripes using the instructions in the 
gstripe man page, I created stripes with a size of 128K as indicated in 
the example.  Performance doesn't seem nearly as good as it did with the 
vinum stripe.  However I don't really know how to test this.

So does the recommendation of a larger stripe size from the vinum and 
tuning docs hold true for geom_stripe?  Or is geom_stripe different in 
some way and the smaller stripe sizes are better.  What are some 
recommended stripe setups for my situation?

Thanks for your input,

Drew

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