Re: is there a COW inside the kernel ?

[Kevin Corry]

On Fri March 3 2006 3:29 pm, roland wrote:
> i think i will take a closer look on device-mapper, but i'm unsure if it`s
> perfectly suited.
>
> can i only use devices, not files for the cow?

Yes, Device-Mapper can only map to block-devices. If you need to do this with 
files, you could use losetup to create block-device from them. However, the 
COW device still won't "grow" automatically as you described.

> what about merging a cow-dev/file back to the r/o-dev/file ?

Device-Mapper does not directly support this, but EVMS provides a "rollback" 
function for reverting an origin volume back to the contents of its snapshot 
volume.

-- 
Kevin Corry
kevcorry@xxxxxxxxxx
http://www.ibm.com/linux/
http://evms.sourceforge.net/
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