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A comment on The New Linode Cloud: SSDs, Double RAM and much more. Parent comment

Re:The New Linode Cloud: SSDs, Double RAM and much more by kyrra on Thursday April 17, 2014 @11:50AM (#7604347)
You're probably right. Do you think it's cache at the VM level before writing to disk. Would writing more data out help at all?

  $ dd bs=1M count=40960 if=/dev/zero of=test conv=fdatasync
  40960+0 records in
  40960+0 records out
  42949672960 bytes (43 GB) copied, 48.455 s, 886 MB/s
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Re:The New Linode Cloud: SSDs, Double RAM and much more by mindslight on Thursday April 17, 2014 @12:28PM (#7604574)
The VM should always pass through proper fsync() semantics, so probably not that layer. But they mention battery-backed raid controllers, and it would be appropriate for fsync() to complete after the data has gotten into battery-backed memory, but before it gets to the actual disks.

(Okay Linode, you've finally done it. I'll get rid of my oddball $30/mo plan sometime soon. That extra $10 used to get me a necessary 180MB of extra RAM!)

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