Im using the two channels from my motherboard, and two channels from one
Abit HotRod 66 PCI controller card.
Ive heard good things about the promise card, but dont know wether you can
have more than one of them on a machine.
You can have 2 devices on each channel (i.e. one master and one slave), most
motherboards have 2 channels (primary and secondary), totalling 4 devices,
however the addin controller card provides another 2 channels (another 4
devices) to give you a maximum of 8 devices on 4 channels. This is linux's
limitation as to maximum number of drives (so 2 controller cards wont help).
If you have 2 devices on one channel then its going to slow down your
performance. From the tests ive done with 2 devices the performance suffers
only in random seeks. In sequential i/o i found only a marginal performance
decrease having both devices on one cable. However i havent been able to
repeat this with 3 or 4 drives, im still finding my way, so maybe my results
wernt distorted somehow.
If you only used your atapi cdrom/floppy (its a 120MB ide thing?)
occasionally you might be prepared to just have them as a slave on the same
channel as a hdd. It depends how much you use them.
The other thing you might concider is a hardware IDE raid controller this
could remove the number of drives limitation, and lower cpu usage for
raid4/5 performance, cost a bit more though, ive never played with one
myself :(
Hope this helps
> Hello Glenn,
>
> My name is Chris Gantz and I am also currently in the process of
configuring a
> very similar configuration to yours. However, I was wondering what IDE
> controller
> are you using for your 4 IDE drives and whether or not you have access to
both
> your floppy and ATAPI CDROM. My Ideal configuration would be to have two
> controllers
> controlling two hard drives a piece, however, I would also like to have
access
> to
> both my floppy drive and ATAPI CDROM. Although I was told that an IDE
> controller can
> only support two devices per controller. Therefore, I am trying to
determine
> what
> is the best way to setup my raid prototype machine with two IDE
controllers and
> whether
> or not it is even possible
>
> Thanks in advance for any info...
>
> Glenn McGrath wrote:
> >
> > Hi, im trying to setup and ide software raid, i have 4 IDE drives each
> > operating on there own channel (using external hpt-366 chipset
controller).
> >
> > I setup raid5 with 4x5GB partitions i got it working ok, but CPU usage
is
> > sitting at 30% when im not doing anything.
> > Its running on a AMD K6-2 266 128MB ram
> >
> > Is it normal to have a high CPU usage like this?
> >
> > Also in raid0 mode i got around 25MB/s i had read that with raid0
> > performance increased nearly linearly.
> > I teasted each drive individually with hdparm -t and the slowest drive
got
> > 14MB/s so i was hoping i would have been able to get above 40MB/s in
raid0.
> >
> > I have only been experimenting with raid or a week or so, im using
2.2.10
> > with the raid0145 patch and uniform-ide patch (for my controller)
> >
> > Any assistance or advice would be apreciated,
> >
> > Thanks
> > Glenn McGrath
>
> --
>
>
////////////////////////////////////////////////////////////////////////////
> // //
> // Christopher A. Gantz, MTS email: [EMAIL PROTECTED] //
> // Lucent Technologies, Bell Labs Innovation //
> // Rm 37W07, 11900 N. Pecos St. voice: (303) 538-0101 //
> // Westminster, CO 80234 fax: (303) 538-3155 //
> // http://info.dr.lucent.com/~cgantz //
> // //
>
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>
