disk devices speed is ugly

Alex Samorukov ml at os2.kiev.ua
Sun Feb 12 17:34:34 UTC 2012

On 02/12/2012 01:54 AM, Adrian Chadd wrote:
> Hi,
> What about the disk access is unaligned? Do you mean not sector aligned? or?
Hi. Sector aligned.
> This is a common problem people face doing disk IO analysis.
> The whole point about not allowing unaligned access is to make the
> disk IO path cleaner. It does mean that the filesystem code (and GEOM
> modules involved) need to be smarter.
> If the filesystem is doing ridiculously unaligned access then it
> likely should be fixed.
Yes. But it will nit fix non-cached access to the disk (raw) devices. 
And this is the main reason why ntfs-3g and exfat are much slower then 
working on Linux.

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