[root@node2 ]# dd if=/dev/zero of=test bs=1M count=20 oflag=direct
20+0 records in
20+0 records out
20971520 bytes (21 MB) copied, 1.12565 s, 18.6 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=20 oflag=direct
20+0 records in
20+0 records out
20971520 bytes (21 MB) copied, 0.885239 s, 23.7 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=200 oflag=direct
200+0 records in
200+0 records out
209715200 bytes (210 MB) copied, 13.1979 s, 15.9 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=200 oflag=direct
200+0 records in
200+0 records out
209715200 bytes (210 MB) copied, 11.448 s, 18.3 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=50 oflag=direct
50+0 records in
50+0 records out
52428800 bytes (52 MB) copied, 1.30443 s, 40.2 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=50 oflag=direct
50+0 records in
50+0 records out
52428800 bytes (52 MB) copied, 0.780204 s, 67.2 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=50 oflag=direct
50+0 records in
50+0 records out
52428800 bytes (52 MB) copied, 1.00842 s, 52.0 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=50 oflag=direct
50+0 records in
50+0 records out
52428800 bytes (52 MB) copied, 0.840131 s, 62.4 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=50 oflag=direct
50+0 records in
50+0 records out
52428800 bytes (52 MB) copied, 0.807058 s, 65.0 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=500 oflag=direct
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 14.7378 s, 35.6 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=500 oflag=direct
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 11.8176 s, 44.4 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=500 oflag=direct
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 33.2182 s, 15.8 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=500 oflag=direct
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 9.97312 s, 52.6 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=500 oflag=direct
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 10.7201 s, 48.9 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=500 oflag=direct
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 11.4589 s, 45.8 MB/s
[root@node2 ]# dd if=/dev/zero of=test bs=1M count=500 oflag=direct
500+0 records in
500+0 records out
524288000 bytes (524 MB) copied, 10.8372 s, 48.4 MB/s