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Date:      Mon, 10 Aug 2015 11:55:51 +0200
From:      Ahmed Kamal <email.ahmedkamal@googlemail.com>
To:        Da Rock <freebsd-fs@herveybayaustralia.com.au>
Cc:        Willem Jan Withagen <wjw@digiware.nl>, Ahmed Kamal via freebsd-fs <freebsd-fs@freebsd.org>
Subject:   Re: Urgently need some help solving lost space due to snapshots during receive op
Message-ID:  <CANzjMX4MeL=M1_oXKHKG-wPv%2B_=w=q_mfttscFgnDpYLFqyFBA@mail.gmail.com>
In-Reply-To: <55C872FD.1060608@herveybayaustralia.com.au>
References:  <55C82BCD.2050404@herveybayaustralia.com.au> <55C863DE.3000200@digiware.nl> <55C872FD.1060608@herveybayaustralia.com.au>

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Try setting compression=lz4 on the target pool .. that might shave off some
space especially if the source wasn't compressed

On Mon, Aug 10, 2015 at 11:46 AM, Da Rock <
freebsd-fs@herveybayaustralia.com.au> wrote:

> On 10/08/2015 18:42, Willem Jan Withagen wrote:
>
>> On 10-8-2015 06:42, Da Rock wrote:
>>
>>> I'm trying to move a pool from one system to another - exact same hdd
>>> and config, different in other areas. Both register same space
>>> available, and so should be no issue. The old system is quite full -
>>> still at least 5% free though.
>>>
>> Hi,
>>
>> Are the versions of your FreeBSD also equal?
>>
> No. 9.1 to 10.1.
>
>>
>> Because in newer version, the free space reservation is significantly
>> bigger. So if disks are equal size, then with newer FreeBSDs you have
>> less usable space available.
>> Don't know the exact SVN commit where it happened. But there are more
>> question on this topic in the list, and they all boil down to the same
>> thing: ZFS needs more reserved space to be able to do certain things
>> without freezing the system.
>>
>> I've not read any suggestions that you can circumvent this setting.
>>
> Crap. So I guess my best will be to compress as best I can for the moment
> or something like that.
>
>>
>> As a second note I think is is more or less general understanding that a
>> ZFS systeem needs a lot more space left free than 5% to actual be able
>> to perform.
>> Last number I remember as sensible maximum fill level is around 70%.
>> If you go over it, your system is going to be busy with ZFS bookkeeping
>> instead of data storage.
>>
> Yeah, I noticed that. Something I'm working on... backlog of sorting
> activities really :) Once I'm done it'll drop to well below 50% I'd say.
>
>> (One of the things I remember from the ZFS lecture by Kirk McKusik,
>> which I no longer can find on YouTube :( )
>>
>> --WjW
>>
> Thanks for the info - I owe you a beer! At least I know why now and eases
> my growing headache from banging my head on the brick wall.
>
>
>> I have done a recursive snapshot on the system and a send/receive over
>>> ssh. Near the end, it final croaks and says no space left. The snapshot
>>> it is sending is nowhere to be found on the receiving system.
>>>
>>> Ok, checked free space - should be enough - so I try a simple cp op on
>>> the last dataset, but then it again croaks no space near the end, but at
>>> least I have some data.
>>>
>>> Checking space again, it says free space of an expected value, but still
>>> won't allow further data.
>>>
>>> I can't seem to figure out why this is not working, I'm currently trying
>>> using compression on the dataset to see if it can't squeeze it on there,
>>> but I still have a couple of no space messages so far.
>>>
>>> Where has my space gone?!
>>>
>>> TIA
>>> _______________________________________________
>>> freebsd-fs@freebsd.org mailing list
>>> http://lists.freebsd.org/mailman/listinfo/freebsd-fs
>>> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"
>>>
>>
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