[PVE-User] Analysis of free space...

[Marco Gaiarin]

Mandi! Alwin Antreich
  In chel di` si favelave...

>>     OK. But this can explain some data, not 20TB of not reclaimed space; and, as
>>     just stated, if i delete now (after that i've set discard=on on volume
>>     property) data, space get correctly reclaimed.
> 
> The parity is calculated for data written and by the docs [0], it is 8K zvol
> block + 4K parity (50%). See also the openzfs docs [1].
> By that calculation you'll need 512 GB for every 1 TB written. That means that
> the 2TB disk will use 3TB on ZFS, plus some extra.

No, sorry; effective space used was a curiosity, not my real question. Sorry
for the misunderstanding.

As just stated:

0) zraid storage created with 'thin provision' enabled.

1) create a bunch of 2TB volumes for a VM, forgot to enable 'discard'.

2) fill VM with DATA

3) delete data from VM.

4) fill again VM with data, space exausted.

5) ops! we have forgot to enable 'discard', enabled it.

6) delete more data (8TB), trim volumes: space reclaimed, but only this 8TB
of data, not the data on point 2.


How can i 'force' some sort of rescan of volumes so trim can happen? Seems
to me that only data deleted after 5) can be reclaimed, the other not.

Actually VM have 20TB of data, pool have 55TB of data. 30TB is expectd, not
55...


I hope i was clear now.

-- 
Marco ``Gaio'' Gaiarin	 | Pordenone Linux User Group  (https://www.pnlug.it/)
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