Re: Kernel Live Patch...

From: Richard Weinberger
Date: Fri May 08 2015 - 14:28:05 EST


On Fri, May 8, 2015 at 8:04 PM, Dennis Ullrich <dennis1ullrich@xxxxxx> wrote:
> Dear all,
>
> I want to make a proposal which is similar to online kernel patching without
> reboot... The idea is to do something which could work similar to the live
> kernel patching method. I don't know how difficult it would be, to implement
> my proposal, but here it comes.
>
> For example I have a HDD with one partiton and a Oracle DB on the ext4
> filesystem. I want to migrate it live to another storage (for example a LPFC
> LUN via Multipath) with all processes etc. on the FS.
> My idea is to modify the IOStack that it is able to make a "bitwise" copy
> and "simply" move the Filesystem to its new place on a blockdevice.
> The point is, to have control about the copy-progress and tell the IOStack
> which device is to use for the requested data, on every access. When the
> copy is done, the admin should be able to remove the old drive. All
> processes should be on the new blockdevice after the movement.
>
> What do you think about this idea?

Why can't you stop the application for a jiffy?
Live patching and stuff is nice but if your service can't deal with
a short outage of a single application it is simple broken by design.

--
Thanks,
//richard
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