+> > once you get them under heavy load. All of the boxes with IDE get very
+> > choppy and slow feeling. Regardless of the maximum burst rate an EIDE
+> > controller or disk can support, they're just slower than SCSI. Any of the
+>
+> only true for misconfigured ide.
+> "feel" depends mainly on whether you're busmastering or not.
That's simply not true. I do have _only_ U2W-SCSI-Disks in my 650 MHz Athlon
(I guess, the SCSI-Hostadapter is doing busmasteing..) and when I put a BIG
job on my system, it *feels* sloppy.
What I had to acknowledge in the past few days, was that my systems memory is
too small. 128 MB is simply not enough for a speedy CPU like the 650 MHz Athlon.
While I was working with Gimp, it was awfully often paging...
+> > LVD SCSI disks can compile a full kernel in about 2:10, and is still
Yet I have to see a SCSI disk compiling a kernel. - Interesting news! ;-)
+> > responsive under load. Putting IDE disks on any of those machines kills
+> > their responsiveness though.
+>
+> ultra2 scsi is wonderful. it's also expensive. so much so that people
+> who buy it sometimes feel obliged to stretch the truth about ide.
+>
+> yes, you can easily achieve 2:10 on a modern ide system (udma).
Self-compiling Disks as well ? ;) (Sorry, couldn't stand it...)
+> > is a slower chip or you have a cheaper disk subsystem.
Sorry, but somehow my Athlon _did_ feel slow and choppy under heavy load.
I assume, the real bottleneck in this case was the "missing" RAM.
+>
+> basically, modern ide disks sustain >20 MB/s.
+> most modern scsi do better, up to around 40 MB/s.
Who cares? As long as you don't reach the PCI burstrate's throughput, your bus
is twiddling thumbs. (And your CPU may, too)
To reach the sustained throughput of a SCSI disk, I'd have to have two IDE disks,
right? In oder to have the throughput of 2 SCSI disks, I'd have to have four IDE
disks, and so on, right?
So what can I do to replace 4 or more SCSI Disks with IDE-stuff?
And what impact does that mean for my systems performance?
+> ide channels cost around $15 apiece.
+> ide disks are at around $8/GB (verus ~$30/GB for scsi)
You get what you pay for...
Best regards,
Herbert
"I sense much NT in you. - NT leads to bluescreen, bluescreen leads to downtime,
downtime leads to suffering. NT is the path to the dark side. Powerful UNIX is."
- Jedi SysAdmin
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