Re: Adding Drive Space

[Steven Pritchard <steve@silug.org>]

Richard Fifarek said:
> 3ware cards are good if you plan on going the RAID route down the road.

They're also nice for performance.  It seems that connecting a decent
IDE disk to a 3ware card gives you a few percent faster reads and
writes than just connecting it to a standard IDE controller.  (BTW,
note that the 3ware card isn't just an IDE controller.  It's a SCSI
card that you happen to connect IDE disks to.)

For *real* performance, do two disks striped on a 3ware card.  Here
are numbers from a bonnie run on the array that used to hold the
ftp.redhat.com and ftp.debian.org mirrors on ftp.silug.org:

              -------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
IBM 75GXP 500  7065 100.0 21840 28.9  8149 10.1  6061 95.9 24151 15.3 136.1  2.5
stripe    500  7073 100.0 42548 67.1 12731 16.6  6178 97.8 29193 19.2 190.1  3.4

(Note that this was on 2.4.0, which seems to have some performance
issues.  The seeks/sec numbers were *much* higher when I tested on
2.2.16.  Also, I'm pretty sure that block reads should be slower than
block writes.  Still, note the twofold increase in write speed.  I'm
pretty sure that should hold up for reads too, at least on another
kernel.  :)

Oh, and you can take any existing disks and just move them over to the
3ware controller (and get a speed boost).  You can also boot from it.

Steve
-- 
steve@silug.org           | Southern Illinois Linux Users Group
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Steven Pritchard          | http://www.silug.org/
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