On Mon, Mar 18, 2002 at 06:53:53PM -0600, Dave Sherohman wrote:
> On Mon, Mar 18, 2002 at 06:34:06PM -0600, David Blevins wrote:
> > Florin Iucha wrote:
> > > Do not put two harddrives on the same IDE channel.
> > 
> > Really, why?  What could go wrong/right?
> 
> IDE channels tend not to have the extra bandwidth you see on a SCSI
> controller.  One drive can pretty well saturate the channel's
> available capacity, resulting in a performance hit.  Make one the
> primary master and the other the secondary master.
> 
> I don't agree with Florin about getting an additional controller for
> your CDROM, though. 

Bzzzzzt! I didn't say that!

I said: go buy another controller and put the big HDD on it.

You CD-ROM/DVD-ROM will not work (it will work most of the time, but if
you have problems everybody and their uncle will tell you it doesn't work
and they are right) on a Promise/Maxtor IDE controller. Those are made
to work on with ATA (hard-drives) devices and not ATAPI (cd-roms/zips).

>                     CD drives don't normally sustain a very high
> data transfer rate (relative to hard drives) and they also tend to
> sit idle most of the time, so I don't see any reason not to slave it
> to whichever drive sees less use.

Bzzzzt. A CD-ROM slave to a HDD will slow down the HDD. And will force
the HDD to the same PIO mode, slowing it down even more (an 80 gigger is
most likely UDMA100).

> One other option besides Florin's suggestion of backing the small
> drive up to the larger one would be to set up a RAID 1 mirror of that
> 20 G and use the other 60 G of the big drive for your mp3 collection
> or whatever else you can get by without. 

I have an uneasy feeling about unbalanced RAID. Yes it works but...

I have a 256 M root partition that I periodically mirror onto the
other harddrives in the system so I can boot from any copy.

>                                          A little more complex than
> keeping the drives separate and not as good for performance, but the
> system will just keep right on going if either drive fails.  (I'd do
> it, but I'm on a RAID kick right now, buying extra drives and setting
> up RAID on everything I see, whether it's called for or not.
> YMWillProbablyV.)
> 
> Finally, set up swap partitions on both drives and, in fstab, add
> "pri=10" to the options for both of them.  If you force multiple swap
> partitions to the same priority (the pri option), the kernel will
> load-balance across them.  Works quite nicely.

Hmm... it's not worth to put a 80 gig HDD to work just because the
kernel feels like distributing the 2 megs it has to swap. Leave only
data on the 80 gigs and it will sleep when appropriate while the 20
gigger will be still busy with cron jobs and other maintenance.

Cheers,
florin

-- 

"If it's not broken, let's fix it till it is."

41A9 2BDE 8E11 F1C5 87A6  03EE 34B3 E075 3B90 DFE4
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