Amazing speed of Amazon virtual drives

1236402298000 » Tagged as: virtualization

Though people are always coughing up large sums of money, the real bottleneck in both servers and desktop computers is the hard drive. Hard drives find it hard to deliver data as fast as they can be processed. With servers you sometimes find that your network capacity is also used up well before the processor hits 100%. But all that changes with Amazon EC2. The hard drives on Amazon Machine Images is blazing fast. And it isn't even a real hard drive. Consider this typical speed test result:

[[email protected] ~]# hdparm -t -T /dev/sda2 /dev/sda2: Timing cached reads:   874 MB in  2.01 seconds = 434.12 MB/sec

Timing buffered disk reads:  746 MB in  3.03 seconds = 246.27 MB/sec

As you can see, the drive on the AMI can deliver at 246.27 MB/sec which is at least three times as fast as the drives on my desktop and about 50% faster than a software RAID (see here for the result). Amazon is truly Amazing For the record this test was done with Amazon ec2 small machine instance (instance id: ami-2b5fba42). It doesn't have hdparm by default  and it had to be installed with yum. hdparm should be run several times and the average be taken. Detailed test report is below.
Test #1: [[email protected] ~]# hdparm -t -T /dev/sda2 /dev/sda2: Timing cached reads: 874 MB in 2.01 seconds = 434.12 MB/sec Timing buffered disk reads: 746 MB in 3.03 seconds = 246.27 MB/sec Test #2: Timing cached reads:   900 MB in  2.00 seconds = 449.88 MB/sec Timing buffered disk reads:  808 MB in  3.00 seconds = 269.21 MB/sec Test #1: Timing cached reads:   816 MB in  2.01 seconds = 405.57 MB/sec Timing buffered disk reads:  770 MB in  3.02 seconds = 255.39 MB/sec On second partition on the same instance (/dev/sda1 ): Test #1: Timing cached reads:   820 MB in  2.00 seconds = 409.85 MB/sec Timing buffered disk reads:  488 MB in  3.00 seconds = 162.51 MB/sec Test #2: Timing cached reads:   806 MB in  2.01 seconds = 400.77 MB/sec Timing buffered disk reads:  716 MB in  3.01 seconds = 237.77 MB/sec Test #1: Timing cached reads:   908 MB in  2.02 seconds = 449.60 MB/sec Timing buffered disk reads:  746 MB in  3.00 seconds = 248.35 MB/sec
Cached reads average (mean) at 434.12 MB/sec and buffered at 256.96 MB/sec that is more than twice as fast as a Gigabit network card can deliver data
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