Re: [dm-devel] Does dm-thin support GC (garbage collection) ?

[Busby <chaimvy gmail com>]

I created pool without ignore_discard feature, is this the way to
enable discard? I mounted the ext4 with '--discard' args, I will trace
whether the ext4 really issue discard later.
Thanks.

Regards,
Busby


2012/5/8, Joe Thornber <thornber redhat com>:
> On Tue, May 08, 2012 at 03:21:31PM +0800, Busby wrote:
>>    I have tested that the blocks were reused in the other thin-lun of
>> this pool  when deleted a thin-lun .
>>    How can the blocks allocated for the thin-lun be dynamically
>> reclaimed? (use some method like 'discard' to tell the pool which
>> block should be reclaimed and whether the pool can reclaim it ?).
>>    When I mounted a filesystem on a thin-lun, create 4G bytes file
>> firstly, the pool have decreased  4G space, then I deleted the file,
>> the pool did not increase the size as I thought, after this, create a
>> 5G file, then the pool would decrease 1G size. So I think if the
>
> Have you enabled discard support in both the thin-pool _and_ the
> filesystem?  Have you confirmed that the filesystem issues the discard
> in your test scenario?  (eg, via blktrace).
>
> - Joe
>
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