On 01/22/2013 05:34 PM, Darren J Moffat wrote:
> On 01/22/13 16:02, Sašo Kiselkov wrote:
>> On 01/22/2013 05:00 PM, casper....@oracle.com wrote:
>>>> Some vendors call this (and thins like it) "Thin Provisioning", I'd say
>>>> it is more "accurate communication between 'disk' and filesystem" about
>>>> in use blocks.
>>> In some cases, users of disks are charged by bytes in use; when not
>>> using
>>> SCSI UNMAP, a set of disks used for a zpool will in the end be
>>> charged for
>>> the whole reservation; this becomes costly when your standard usage is
>>> much less than your peak usage.
>>> Thin provisioning can now be used for zpools as long as the underlying
>>> LUNs have support for SCSI UNMAP
>> Looks like an interesting technical solution to a political problem :D
> There is also a technical problem too: because if you can't inform the
> backing store that you no longer need the blocks it can't free them
> either so they get stuck in snapshots unnecessarily.

Yes, I understand the technical merit of the solution. I'm just amused
that a noticeable side-effect is lower licensing costs (by that I don't
of course mean that the issue is unimportant, just that I find it
interesting what the world has come to) - I'm not trying to ridicule.

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