Peter Farrow <peter@xxxxxxxxxxx> wrote:
> [root@ ~]# hdparm -t /dev/hdb
> /dev/hdb:
> Timing buffered disk reads: 62 MB in 3.07 seconds =
> 20.17 MB/sec
> [root@ ~]# hdparm -t /dev/hda
> /dev/hda:
> Timing buffered disk reads: 62 MB in 3.02 seconds =
> 20.51 MB/sec
Ouch! They are on the same channel! Furthermore, you're
only getting the cache speed. Try "-Tt" instead. And try
running those 2 commands simultaneously! You're going to see
more than a 50% drop (more like an 80%!).
> UDMA modes: udma0 udma1 *udma2 udma3 udma4 udma5
> UDMA modes: udma0 udma1 *udma2 udma3 udma4 udma5
Ultra DMA mode 2 (33MHz) is a good sign.
> I'm running software RAID and they are both on one IDE
> controller, but this is because the installer detects
> the drive geometry differently for each if they are on
> separate controller,
If it's Award BIOS, then set the geometry to "LBA" in the
BIOS.
Furthermore, _regardless_ of what the BIOS says, once you
partition with LBA, if you move it to another controller, the
partition table will _still_ be LBA when Linux loads the
partitions.
> which would be the best option, but as I am doing mirroring
I
> want the geometry the same.
The geometry is _already_ the same once the partition table
has been created. Linux _ignores_ the BIOS' geometry if it
was partitioned differently.
> Furthermore no amount of changing in the BIOS affects the
> detected geometry by Anaconda. I've seen this quite a lot
on
> Compaqs.
Oh, a Compaq. Yeah, broken BIOS.
But _regardless_, you've already got the correct geometry.
You can now move channels, Linux will read the partition
table and use its geometry -- not what the BIOS says.
ATA DMA was _never_ designed for master/slave, that's an old
EIDE PIO configuration. Drives only allow it to be
compatible, but it's not recommended at all.
--
Bryan J. Smith | Sent from Yahoo Mail
mailto:b.j.smith@xxxxxxxx | (please excuse any
http://thebs413.blogspot.com/ | missing headers)
