[dm-devel] merging dm-ioband into Linux

[Ryo Tsuruta]

Hi Jonathan,

I'm sorry for responding late.

From: Jonathan Brassow <jbrassow at redhat.com>
Subject: Re: [dm-devel] merging dm-ioband into Linux
Date: Thu, 8 Jan 2009 12:05:09 -0600

> Perhaps it will help people to know that there is a good write-up about how it all works at the end of the patch found at:
> http://people.valinux.co.jp/~ryov/dm-ioband/patches/dm-ioband-1.7.0.patch

Thanks for the advice.

> It seem interesting to me.  (I'm still reading through the description and haven't started looking at the code.)

I would also be happy if you give me any comments on the code.

> Regarding:
> +                ioband_device_id
> +
> +                          The ID number for an ioband device. The same ID
> +                        must be set among the ioband devices that share the
> +                        same bandwidth, which means they work on the same
> +                        physical disk.
> ... but it doesn't have to be the same physical disk, right?  It could be a group if disks if you felt the need to do something like that, right?  (You could treat a JBOD as one unit.)  Otherwise, you could probably eliminate this field.

As you wrote, dm-ioband can treat a logical volume on different
physical devices like this:
http://people.valinux.co.jp/~ryov/dm-ioband/benchmark/lvm.html

Thanks,
Ryo Tsuruta