On Mon, Feb 14, 2011 at 1:37 PM, lucianobarreto@xxxxxxxxx
> I need to share some files between VMs. This files will be used to transfer
> some information (read/write). But I need do it without any network resource
> (NFS or others). I've tried to do it sharing a partition just for test
> proposes, but i see that when i create a file on one VM another can't see it
> and there isnt any concurrence in this approach.
> Anyone can help me??
to share files, you need a shared filesystem. there are two main
classes of these:
- network filesystems: NFS, Samba, 9p, etc. these work really well;
you shouldn't reject them without good reason.
- clustered filesystems: GFS, OCFS2, CXFS, etc. they're designed for
SAN systems where several hosts access the same storage box. in VM
case, if you create a single partition accessible from several VMs you
get exactly the same situation, (shared block device) and need the
what definitely won't work is to use a 'normal' filesystem (ext3/4,
XFS, ReiserFS, FAT, HPFS, NTFS, etc) on a shared partition (just like
it won't work in a shared block device). Since every filesystem
aggressively caches metadata to avoid rereading the disk for every
access, a VM won't be 'notified' if another one modifies a directory,
so it won't 'notice' any change. and worse, since now the cached
metadata isn't consistent with the content of the disk, any write will
result in a heavily corrupted filesystem.
better go with NFS
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