

Disk IO Performance: EC2 vs Mosso vs Linode - wmf
http://blog.mudy.info/2009/04/disk-io-ec2-vs-mosso-vs-linode/

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wheels
Unfortunately these numbers don't really mean much. Aside from what else is
happening on the machines, in some cases note that writing was showing up
faster than reading, which really means that it's just writing things to disk
buffers. For this test to have been meaningful there should have been an fsync
at the end of the run. The direct-i/o measurements should be closer to apples-
to-apples.

When I'm doing I/O benchmarking I start every run with a clean reboot and
follow an exact set of steps from bootup to start of the benchmark. It's
almost impossible to simulate that on a VPS.

------
lsc
the problem with benching a VPS is that your score depends a whole lot on what
your neighbors are doing. For a fair test, you want to re-run the test a
number of times over a period of days.

~~~
grandalf
or if you use Joyent you get slow IO even if you're the only zone on the
hardware!

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friism
The interesting number (for most DB workloads anyway) is IOPS or seeks/sec in
the article. EBS, as espected, is ferocious.

~~~
lsc
you probably also don't want to run a DB on non-raid disk. I believe the ec2
instances have non-mirrored disk, I mean, if you are not using ebs. (if you
don't care about the data, use something with more ram, and mount the disk
async. Ram is going to be faster than disk, always.)

~~~
yejun
The problem is that DB application will try to sync disk either via fsync or
o_direct. EBS may have a very long latency for such kind access.

~~~
lsc
I'm just pointing out that you don't want to run your db on non-redundant
disk. Really, I think in-ram, redundant databases like MySQL cluster are more
suited to the 'cloud' - especially as you can get cheap ram.

Just looking at the bonnie results, ebs wasn't that far off everything else in
terms of sequential access.

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rjurney
The IO on the EC2 medium compute instances is not good. Would be interested in
seeing a large instance compared.

I did a ginormous RAID 0 on EBS on a large EC2 instance, and the IO tests were
quite disappointing.

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ShabbyDoo
I would not be surprised if Amazon does not soon offer faster EBS at a
premium. They ought to be doing the RAID stuff, not the individual EC2 user.

