Messages in this thread | | | Date | Thu, 29 May 2008 12:08:15 -0400 | From | Rik van Riel <> | Subject | Re: [help]How to block new write in a "Thin Provisioning" logical volume manager as a virtual device driver when physical spaces run out? |
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On Thu, 29 May 2008 11:31:59 +0100 Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
> > Does anyone have some ideas for a better solution? > > Take one file system such as ext3, or even a cluster file system like > GFS2 or OCFS. Create top level subdirectories in it for each machine. > Either export the subdirectory via NFS.
Xiaoming, let me point out another advantage of Alan's approach.
In a block based thin provisioning system, like you proposed, there is no way to free up space. Once a user's filesystem has written a block, it is allocated - when the user deletes a file inside the filesystem, the space will not be freed again...
This means that once the disk is full it will stay full, no matter how many files are deleted in the guest filesystems. Overcommitting an unfreeable resource is a bad idea.
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