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Re: [Xen-users] crazy SWAP and RAM idea

To: "SH Solutions" <info@xxxxxxxxxxxxxxx>
Subject: Re: [Xen-users] crazy SWAP and RAM idea
From: "Christoph Purrucker" <cp+ml-xen@xxxxxxxx>
Date: Fri, 8 Sep 2006 13:03:52 +0200 (CEST)
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Hi Steffen,

> The idea to solve this, is a follows:
> 1. Give every domU as few memory as possible. (16MB?)
> 2. Give dom0 a huge fast swap space (several GB?)
> 3. Create a "RAMDRIVE" in dom0 in that swap.
> 4. Create domU's swap partitions on dom0's ramdrive.
> The reason would be that dom0 can now "really" swap in pages as *REALLY*
> needed from/to harddrive.
> DomU's would then "only" swap from/to a partition that really is RAM and
> as such really fast.

- You have no file system cache any more.
- Swapping in a ramdrive means to double-memcopy and many overhead.
- You may swap-to-death Dom0 because the memory needed by tmpfs will swap
out other important Dom0 processes.

But feel free to try it and write your results here.

cu cp

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