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From: =?UTF-8?Q?Piotr_Paw=c5=82ow?= <pp@siedziba.pl>
Subject: Re: Shrinking a device - performance?
To: Peter Grandi <pg@btrfs.list.sabi.co.UK>,
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> The proposed "move whole chunks" implementation helps only if
> there are enough unallocated chunks "below the line". If regular
> 'balance' is done on the filesystem there will be some, but that
> just spreads the cost of the 'balance' across time, it does not
> by itself make a «risky, difficult, slow operation» any less so,
> just spreads the risk, difficulty, slowness across time.

Isn't that too pessimistic? Most of my filesystems have 90+% of free
space unallocated, even those I never run balance on. For me it wouldn't
just spread the cost, it would reduce it considerably.