[rhelv6-beta-list] My first experiences with RHEL6 beta

[Chris Adams]

Once upon a time, James Findley <james.findley at trans-axion.net> said:
> On 06/15/2010 02:20 PM, Chris Adams wrote:
> >Once upon a time, James Findley<james.findley at trans-axion.net>  said:
> >>There is a (small) overhead for using file-based storage as opposed to
> >>volume based storage,
> >
> >The only differences is at "swapon", when the file blocks are mapped.
> >Once that is done, performance is identical (because access is
> >identical).
> 
> Not entirely.  swap files can be non-contiguous (and are moderately 
> likely to be so, if large) - swap volumes will only be so if you try 
> really hard to screw up your system.

The blocks of each are mapped at swapon and used directly.

> There are filesystem overheads, too.

Nope, swap bypasses the filesystem.

> I'm not quite sure why you think access is identical - it's a very 
> different process to write N blocks to an on-disk file compared to 
> writing those N blocks to a swap partition.

Because when this was discussed on the kernel mailing list, Andrew
Morton explained all these things and said they have the same
performance after swapon.  I'll take his word for kernel things.

-- 
Chris Adams <cmadams at hiwaay.net>
Systems and Network Administrator - HiWAAY Internet Services
I don't speak for anybody but myself - that's enough trouble.