On 2008/10/23 02:48 (GMT-0500) David C. Rankin composed:
I ran a comparison on an old file server just to check disk performance of the backup machine. I compared it to a new machine and the difference validates Mohr's law:
[AMD K62-450 w/2 20G IBM Deskstar 7200 rpm drives]
sudo hdparm -tT /dev/sda /dev/sda: Timing cached reads: 72 MB in 2.00 seconds = 35.94 MB/sec Timing buffered disk reads: 26 MB in 3.09 seconds = 8.41 MB/sec
Almost certainly UDMA33, which dates back to around 11 years ago. I'm not aware of any Socket 7 chipsets that supported UDMA66. If your K6/2-450 was state of the art speed when its motherboard was acquired, it would probably have pre-dated UDMA66 anyway.
[AMD Phenom 9850 w/2 500G Seagates in RAID1]
/dev/sda: Timing cached reads: 3504 MB in 2.00 seconds = 1751.75 MB/sec Timing buffered disk reads: 188 MB in 3.02 seconds = 62.33 MB/sec /dev/sdb: Timing cached reads: 3494 MB in 2.00 seconds = 1746.89 MB/sec Timing buffered disk reads: 200 MB in 3.01 seconds = 66.53 MB/sec
/dev/dm-0: Timing cached reads: 3432 MB in 2.00 seconds = 1716.32 MB/sec Timing buffered disk reads: 194 MB in 3.02 seconds = 64.27 MB/sec
SATA 300 probably, which itself needs a test of Moore's law. I doubt you'll find a doubling over real world performance of an equivalent system only 18-24 months older.
The Software RAID penalty -- virtually non-existent as far as hdparm is concerned.
The results are astounding when you think what has happened in just a few years...
More like 9 years (UDMA33 to SATA300), in which of late the law has been breaking down. Still, what we have now begs the question how fast is fast enough. I stopped being impressed with "faster" 5 years ago, around the time gigabit ethernet and then DDR2 RAM hit the street. Even with FIOS the internet is most often the bottleneck noticed by the face in front of the display, and a big bottleneck it is. -- "Everyone should be quick to listen, slow to speak, and slow to become angry." James 1:19 NIV Team OS/2 ** Reg. Linux User #211409 Felix Miata *** http://fm.no-ip.com/ -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org