-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 It is okay to do concurrent mounts if _all_ of the mounts are RO, right? I frequently have many VM's mounting the same DVD iso (RO, of course). Should I be anticipating disaster? David King Goshen College ITS davidwk@goshen.edu 574-535-7726 On 02/04/2011 05:14 AM, Daniel P. Berrange wrote:
On Fri, Feb 04, 2011 at 04:29:35AM -0500, Dale Amon wrote:
I suspect the answer is no, as the very idea makes my head hurt, but a confirmation would be nice:
Am I correct in assuming that it is a very bad idea to mount a physical disk on both the physical machine and on a hosted VM at the same time?
I can imagine getting away with it if one were RO, but not otherwise.
Even readonly is not safe. If the host OS has a RO mount and has partial FS metadata cached, then the guest OS writes to the FS, this might invalidate the host metadata and potentially confuse the host OS enough that it would crash if you're unlucky.
If you want safe concurrent mounts then you need a clustered or network filesystem. You can also use libguestfs for readonly access to live guest disks (still has the potential problem I mention above, but libguestfs runs in a VM so it avoids any risk to your host OS)
Daniel -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
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