[Beowulf] VMC - Virtual Machine Console

Joe Landman landman at scalableinformatics.com
Fri Mar 7 08:57:35 PST 2008

Peter Skomoroch wrote:

> Extra Large Instance:
>       15 GB memory
>       8 EC2 Compute Units (4 virtual cores with 2 EC2 Compute Units each)
>       1,690 GB instance storage (4 x 420 GB plus 10 GB root partition)
>       64-bit platform
>       I/O Performance: High

Note:  minor criticism, but overall, nice results.

Looking over your bonnie results is worth a quick comment.  Any time you 
have bonnie or IOzone (or other IO benchmarks) which are testing file 
sizes less than ram size, you are not actually measuring disk IO.  This 
is cache speed pure and simple.  Either page/buffer cache, or RAID 
cache, or whatever.

We have had people tell us to our face that their 2GB file results (on a 
16 GB RAM machine) were somehow indicative of real file performance, 
when, if they walked over to the units they were testing, they would 
have noticed the HD lights simply not blinking ...  Yeah, an amusing 
beer story (the longer version of it), but a problem none-the-less.

Your 1GB file data is likely more representative, but with 15 GB ram, 
you need to be testing 30-60 GB files.

Not trying to be a marketing guy here or anything like that ... we test 
our JackRabbit units with 80GB to 1.3TB sized files.  We see (sustained) 
750 MB/s - 1.3 GB/s in these tests.  We also note some serious issues 
with the linux buffer cache and multiple RAID controllers (buffer cache 
appears to serialize access).  We do this as we actually want to measure 
disk performance, and not buffer cache performance.

That criticism aside, nice results.  It shows what a "cloud" can do.

>       Price: $0.80 per instance hour

Joseph Landman, Ph.D
Founder and CEO
Scalable Informatics LLC,
email: landman at scalableinformatics.com
web  : http://www.scalableinformatics.com
phone: +1 734 786 8423
fax  : +1 866 888 3112
cell : +1 734 612 4615

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