new hard drive trouble

Shane Hathaway shane at hathawaymix.org
Sat Dec 30 22:24:34 MST 2006


Brian Beardall wrote:
> I would get the sata II controller. The advantage of the sata II
> controller is the addition of NCQ. NCQ is what helps make SCSI drives so
> appealing and fast. NCQ is not available on most sata I contollers. If
> you have PCI Express on your motherboard you should be able to get a
> sata II contoller for about $30. If you only have PCI then you can get
> one for about $63. Sata II is also backwards compatible with Sata I and
> so it is a win win situation buying a sata II contoller.

You may be correct, but here's my experience.  Until a month ago I used
a SATA I drive and controller; now I'm using a SATA II drive and
controller.  Differences:

- According to "hdparm -t", the SATA I drive was limited to 55 MB/s.
The SATA II drive is limited to 76 MB/s.  Both 7200 RPM.  (The 10K RPM
drives I've experimented with could transfer 90 MB/s.)

- Although I have NCQ now, I haven't noticed any differences.  I would
expect NCQ to more fairly balance I/O requests between processes, but I
haven't seen any sign of that.  However, I don't know of a quantitative
measure of this.

- I suspect the choice of filesystem may be more important than the
choice of controller.  I used to store all my MythTV programs using XFS.
 I switched to ext3 on LVM so that I could shrink the partition at a
later time.  However, it turns out XFS was nicer to the disk while
recording (less seeking), and it was a lot faster at deleting multi-GB
files.

So an option to consider is to buy the less expensive card now and save
for a new sub-$100 motherboard with PCI Express, SATA II, gigabit NIC, 8
built in USB ports, etc., etc.

Shane




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