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[Xen-devel] Re: [Xen-users] How to share data between guest domains

I found that using NFS for things like this makes much more sense.
You can run the domU with NFS root (read-only) and map certain areas you
need read/write
to tmpfs by mounting them with "mount --bind" in Linux). For example, if
I use NFS root and want my /etc
be writable I can always write its content to a tmpfs mounted area and
run "mount --bind /tmpfs/etc /etc".
This also will solve problems with centralized package updates when not
only /usr is being updated, but some other areas (eg. /etc, /var/lib).
You want those areas be shared between domU's as well.

Molle Bestefich wrote:

>Todd D. Esposito wrote:
>>However, on that note, I wonder if you could mount the same file system,
>>say something like /usr, into multiple domU's READ ONLY.
>That works for me.
>What doesn't work is mounting that file/device READ/WRITE in one domU
>to update the filesystem.  For that, I have to take down *all* domUs. 
>Not good...
>(When I try I get a vbd: error saying "already in use".)
>(I know about caching and that I need eg. a cluster-aware filesystem
>to do this.)
>I've spent a couple of hours hunting through various Xen source files.
> There's a lot of Python functions that are only 3-5 lines long and
>which does little else than calling the next function, which makes it
>very hard to figure out what's going on :-/.
>Could one of you devel guys please let me know where I need to go to
>remove this silly limitation? :-)
>Xen-users mailing list

Yuri Pismerov, System Administrator
Armor Technologies (Canada) Inc.

P: 905 305 1946 (x.3519)

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