Hacker News Reader

Comment by Nux | Hacker News Reader

Throughput speed is not everything, in many situations latency is more important. Can you give results for this?

dd if=/dev/zero of=test bs=512 count=1500 oflag=dsync

I'm getting "6.40264 s, 120 kB/s" on my laptop's SSD, but on a proper server with a RAID card and cache enabled I get "0.187033 s, 4.1 MB/s".

View on HN

I did 7 runs of your test and the average time is: 0.424795s. Example run:

  $ dd if=/dev/zero of=test bs=512 count=1500 oflag=dsync
  1500+0 records in
  1500+0 records out
  768000 bytes (768 kB) copied, 0.427272 s, 1.8 MB/s

DO @5$/mo:

    $ dd if=/dev/zero of=test bs=512 count=1500 oflag=dsync         
    1500+0 records in
    1500+0 records out
    768000 bytes (768 kB) copied, 1.64471 s, 467 kB/s

DO @$40-AMS1

  1500+0 records in
  1500+0 records out
  768000 bytes (768 kB) copied, 1.17399 s, 654 kB/s

dd if=/dev/zero of=test bs=512 count=1500 oflag=dsync 768000 bytes (768 kB) copied, 0.3325 s, 2.3 MB/s

dd if=/dev/zero of=test bs=512 count=1500 oflag=dsync

768000 bytes (768 kB) copied, 0.45329 s, 1.7 MB/s

Reply on news.ycombinator.com