[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] how to see the data changing in a running domain?



> So clearly everything made changed inside domainU cannot be seen from
> outside (domain0).
> Anybody can please explain to me why, and if 
> possible, how could I watch data of domainU (in realtime) from
> domain0?

The DomU will be caching the updates to its disk in memory before writing them 
to the disk.  Likewise, Dom0 will be caching data it's read and assuming it 
stays the same (most filesystems assume only one writer, so dom0 thinks it 
knows when the disk is modified).

The result of this is that dom0 won't immediately notice the changes domU has 
made.  When it does notice, it'll likely take the form of an error along the 
lines of "Something changed on this filesystem that I wasn't expecting."

As Ian says, the GFS and OCFSv2 filesystems are explicitly aware of concurrent 
access so they'll cope with this OK.

The easiest solution for your purposes would be to use NFS root in the domU 
(with the root FS exported from dom0) or to run an NFS server in the domU and 
export the root FS to dom0.

HTH,
Mark


-------------------------------------------------------
This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting
Tool for open source databases. Create drag-&-drop reports. Save time
by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc.
Download a FREE copy at http://www.intelliview.com/go/osdn_nl
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.sourceforge.net/lists/listinfo/xen-devel


 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.