What about CPU usage? What happens when you put it into one or more raids, what are then your combinde performance? Did you experiment with different raid types? best regards keld On Sun, Jan 04, 2009 at 09:27:28PM -0600, Matt Garman wrote: > On Sun, Jan 04, 2009 at 03:02:37PM -0600, Roger Heflin wrote: > > Yes, that is valid, so long as the md device is fairly quiet at > > the time of the test. Since you already have a machine, please > > post the mb type, and number/type of sata ports and the 1-disk, > > 2-disk, 3-disk,... numbers that you get. > > I attached a little Perl script I hacked up for running many > instances of dd in parallel or individually. It takes one or more > block devices on the command line, and issues parallel dd reads for > each one. (Note my block size and count params are enormous; I made > these huge to avoid caching effects of having 4 GB of RAM.) > > I have two MD arrays in my system: > > $ cat /proc/mdstat > Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10] > md1 : active raid5 sdb1[0] sdd1[3] sdc1[2] sde1[1] > 2930279808 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU] > > md0 : active raid5 sdf1[0] sdi1[3] sdh1[2] sdg1[1] > 2197715712 blocks level 5, 64k chunk, algorithm 2 [4/4] [UUUU] > > unused devices: <none> > > > This is on Ubuntu server 8.04. Hardware is an Intel DQ35JO > motherboard (Q35/ICH9DO chipsets) with 4 GB RAM and an E5200 CPU. > > - md1 has four WD RE2 GP 1 TB hard drives (the 5400 RPM ones). > These are drives are connected to two 2-port PCIe SATA add-on > cards with the Silicon Image 3132 controller. > > - md0 has four WD 750 GB drives (neither "RE2" version nor > GreenPower). These drives are connected directly to the > on-board SATA ports (i.e. ICH9DO). > > For md1 (RE2 GP drives on SiI 3132), it looks like I get about 80 > MB/s when running dd on one drive: > > $ sudo ./sata_performance.pl /dev/sd[b] > /dev/sdb: 13107200000 bytes (13 GB) copied, 163.757 s, 80.0 MB/s > > With all four drives, it only drops to about 75 MB/s per drive: > > $ sudo ./sata_performance.pl /dev/sd[bcde] > /dev/sdb: 13107200000 bytes (13 GB) copied, 171.647 s, 76.4 MB/s > /dev/sde: 13107200000 bytes (13 GB) copied, 172.052 s, 76.2 MB/s > /dev/sdd: 13107200000 bytes (13 GB) copied, 172.737 s, 75.9 MB/s > /dev/sdc: 13107200000 bytes (13 GB) copied, 172.777 s, 75.9 MB/s > > For md0 (4x750 GB drives), performance is a little better; these > drives are definitely faster (7200 rpm vs 5400 rpm), and IIRC, the > SiI 3132 chipsets are known to be lousy performers. > > Anyway, single drive performance is just shy of 100 MB/s: > > $ sudo ./sata_performance.pl /dev/sd[f] > /dev/sdf: 13107200000 bytes (13 GB) copied, 133.099 s, 98.5 MB/s > > And I lose virtually nothing when running all four disks at once: > > $ sudo ./sata_performance.pl /dev/sd[fghi] > /dev/sdi: 13107200000 bytes (13 GB) copied, 130.632 s, 100 MB/s > /dev/sdf: 13107200000 bytes (13 GB) copied, 133.077 s, 98.5 MB/s > /dev/sdh: 13107200000 bytes (13 GB) copied, 133.411 s, 98.2 MB/s > /dev/sdg: 13107200000 bytes (13 GB) copied, 138.481 s, 94.6 MB/s > > Read performance only drops a bit when reading from all eight > drives: > > $ sudo ./sata_performance.pl /dev/sd[bcdefghi] > /dev/sdi: 13107200000 bytes (13 GB) copied, 133.086 s, 98.5 MB/s > /dev/sdf: 13107200000 bytes (13 GB) copied, 135.59 s, 96.7 MB/s > /dev/sdh: 13107200000 bytes (13 GB) copied, 135.86 s, 96.5 MB/s > /dev/sdg: 13107200000 bytes (13 GB) copied, 140.215 s, 93.5 MB/s > /dev/sdb: 13107200000 bytes (13 GB) copied, 182.402 s, 71.9 MB/s > /dev/sdc: 13107200000 bytes (13 GB) copied, 183.234 s, 71.5 MB/s > /dev/sdd: 13107200000 bytes (13 GB) copied, 189.025 s, 69.3 MB/s > /dev/sde: 13107200000 bytes (13 GB) copied, 189.517 s, 69.2 MB/s > > > Note: in all the above test runs, I actually ran them all three > times to catch any variance; all runs were consistent. > > > I am looking at getting a new AMD solution in the next month or so > > and would like also know which scales reasonably. > > The one I've got my eye on is the GA-MA74GM-S2. It's got six > onboard SATA ports (provided by the SB700 southbridge). > SilentPCReview reviewed this board[1] and found it to have extremely > low power consumption when paired with a 4050e CPU. On that site > and other hardware enthusiast sites, there are a lot of people using > it for home NAS/fileserver boxes. I thinking about picking one up > to replace this Intel board and CPU; if I do, I'll report back the > results. > > [1] http://www.silentpcreview.com/article859-page1.html > > Thanks again! Hope someone finds this info useful. > > Matt > > #!/usr/bin/perl > > # License: public domain > > use strict; > > my $dd="/bin/dd"; > my $bs="128k"; > my $count="100000"; > > my @pids; > for my $dev (@ARGV) > { > my $pid = fork(); > if ($pid == 0) # child > { > my $cmd = "$dd if=$dev of=/dev/null bs=$bs count=$count 2>&1"; > my @output = `$cmd`; > my $n_lines = scalar(@output); > my $rc = $? >> 8; > if ($rc != 0 || $n_lines != 3) > { > print STDERR "ERROR: $dev: return code=$rc, n_lines=$n_lines:\n"; > foreach my $line (@output) > { > print STDERR " " . $line; > } > } > else > { > my $line = $output[2]; > chomp($line); > print "$dev: $line\n"; > } > exit(0); > } > else # parent > { > push(@pids, $pid); > } > } > > for my $pid (@pids) > { > waitpid($pid, 0); > } -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
