Re: Readahead value 128K? (was Re: Drastic Slowdown of 'fseek()'Calls From 2.4 to 2.6 -- VMM Change?)

[Mark Lord]

Marr wrote:
> I tried turning 'readahead' off entirely ('hdparm -A0 /dev/hda') and, although 

No, that should be "hdparm -a0 /dev/hda" (lowercase "-a").
And the same "-a" for all of your other test variants.

If you did it all with "-A", then the results are invalid,
and need to be redone.

The hdparm manpage explains this, but in a nutshell, "-A" is the
low-level drive firmware "look-ahead" mechanism, whereas "-a" is
the Linux kernel "read-ahead" scheme.

In general, most uppercase hdparm flags are drive *firmware* settings.

Cheers
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