[Discuss] linux on usb stick

[Richard Pieri]

Tom Metro wrote:
> VMware caching I/O wouldn't really explain it, if the underlying file
> system is still on a Flash device, which in Stephen's scenario it was.

When running natively, reads and writes are going to queue up behind 
fsync() calls and programs will block. It's unavoidable because flash 
has terrible write performance.

When running in a VM the VM system acknowledges fsync() calls and 
returns an "okay" status without actually performing the sync to disk. 
The virtualized guest will not block until the host blocks. A result of 
this is that you can get performance that appears to exceed the physical 
capabilities of the underlying device.

-- 
Rich P.