Re: RAID5 question.

And notice you can apply different readahead to:
The raw devices (/dev/sda)
The md device (/dev/mdX)
Any lvm device (/dev/lvm_name/lvm_device)

David

Raz Ben Jehuda wrote:

read the blockdev man page

On Thu, 2005-08-04 at 16:06 +0200, djani22@dynamicweb.hu wrote:
 

quoted

Hi list, Neil!

I have a little question because I'v got some performance problem...
Is the RAID5 do any type of headahead with the default config?
It is possible to disable the readahead? (if it is.)
Or just the io_sched do that on the disks?

How can I disable the whole headahead on top of the RAID5 array?

The RAID5 can do multiple small (<4kb) reads of disks for the multithreaded
read requests?
(chunk size is 32k)

Thanks for helping!

Janos

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