Re: 2.6 vm/elevator loading down disks where 2.4 does not

[Ray Lee]

> Upon investigation, we saw that the 2.6 box was reading from the disk
> about 5 times as much as 2.4.

I don't think this will account for the entire change in disk activity,
but 2.6.7-pre? contains a fix for the read ahead code to prevent it from
reading extra sectors when unneeded.

The fix applies to 'seeky database type loads' which...

> The data access patterns are generally "search through index files in
> a tree-walking type of manner, then seek to data records in data
> files."

...sounds like it may apply to you.

So, if you and your server have some time, you might try 2.6.7rc3 and
see if it changes any of the numbers.

Ray Lee

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/