[SATLUG] Filesystem/RAID advice

travis+ml-satlug at subspacefield.org travis+ml-satlug at subspacefield.org
Sun Oct 24 17:45:51 CDT 2010


On Tue, Oct 12, 2010 at 07:38:39PM -0500, Othniel Graichen wrote:
> So in response to "Virtualization DOES slow down the system"

It's a simple fact that emulating something in software takes longer
than doing the native operation in hardware.

That's how us security people are detecting virtualization these days.
In particular, RDTSC takes several orders of magnitude longer.
Case in point:

http://www.codeproject.com/KB/security/AntiReverseEngineering.aspx#TimingA

Given the above, I think the burden of proof is on you to make the
case that trap-and-emulate can be faster than running the exact same
operations natively.

I'm not arguing that NTFS isn't a lousy file system, or that Windows
doesn't suck, I'm just saying that adding a layer of virtualization is
unlikely to _increase_ speed, except in certain cases where you're
somehow improving performance "below" the guest compared to raw
hardware (for example, giving the guest a larger disk buffer than it
could keep natively).
-- 
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