> Thanks Bill, yep I know it will rebuild slowly in the background. I > hadn't filled in the new info I have since no one had responded, and > figured the thread was dead. > > Here's the deal > > I just installed a simple raid-1. I have a single HD on each > controller. ie. 2 controllers 2 HDs. That's it, no CD players or DVD > drives... > > I did a fresh install of Sarge. After reboot I unplugged the CD drive, > and let the array sync overnight. It took 10hrs to sync 160GiB, which > seemed pretty long, so I executed the "dd if=/dev/hda of=/dev/null > bs=64k count=10000" command I've seen posted on the raid list.
Sure, so you are reading 600 MB from /dev/hda > It took about a minute and change to complete, which is long. So out of So about 10MB/sec. > curiosity I plugged in a CD player and booted Knoppix. When I ran the > same command it took only 30 seconds (which is still not as quick as > some of the numbers on that list, but it's an old celeron 466MHz). Right, 2.4 vs 2.6 kernels handle I/O differently, I don't consider dd a very good measurement of performance since read/writes to raw disk devices (without caches, buffering, ordering, or filesystem) are pretty rare. > So Knoppix is configuring something different, I'm searching for the > difference I'd point at both the readahead and the large difference in kernel. > I compared the result hdparm under both OSs > Sarge:~# hdparm /dev/hda > /dev/hda: > readahead = 256 (on) > > knoppix:~# hdparm /dev/hda > readahead = 8 (on) > geometry = 19457/255/63, sectors = 312581808, start = 0 > < Linux version 2.6.8-2-686 ([EMAIL PROTECTED]) (gcc version > --- > > Linux version 2.4.27 ([EMAIL PROTECTED]) (gcc version 2.95.4 20011002 -- Bill Broadley Computational Science and Engineering UC Davis _______________________________________________ vox-tech mailing list vox-tech@lists.lugod.org http://lists.lugod.org/mailman/listinfo/vox-tech