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From: Ede Wolf <>
Subject: Re: [linux-lvm] thinpool metadata got way too large, how to handle?
Date: Fri, 10 Jan 2020 17:30:24 +0100	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>


I am afraid I have been a bit too optimistic. Being a bit embarassed, 
but I am not not able to find any reference to component activation. 
I've deactivated all LVs and tried to set the thinpool itself or its 
metadata into read only mode:

# lvchange -pr VG_Raid6/ThinPoolRaid6
   Command on LV VG_Raid6/ThinPoolRaid6 uses options invalid with LV 
type thinpool.
   Command not permitted on LV VG_Raid6/ThinPoolRaid6.

# lvchange -pr /dev/mapper/VG_Raid6-ThinPoolRaid6_tmeta
   Operation not permitted on hidden LV VG_Raid6/ThinPoolRaid6_tmeta.

I can lvchange -an the thinpool, but then obviously I have no path/file 
for for the thin_repair input anynmore that I could provide.

So please, how do I properly set the metadata into read only?



Am 08.01.20 um 12:29 schrieb Zdenek Kabelac:
> Dne 02. 01. 20 v 19:19 Ede Wolf napsal(a):
>> Hello,
>> While having tried to extend my thinpool LV, after the underlying md
>> raid had been enlarged, somehow the metadata LV has gotten all the
>> free space and now is 2,2 TB in size. Space, that is obviously now
>> missing for the thinpool data LV, where it should have gone in first
>> place.
> Hi
> I might guess you were affected by bug in 'percent' resize logic,
> that has been possibly addressed by this upstream patch:
> Although your observed result of having 2.2TB metadata size looks 
> strange - it should not normally extend the size of LV to this extreme 
> dimension - unless we miss some more context here.
>> And since reducing the metadata LV of the thinpool is not possible, I
>> am now wondering, what options I may have to reclaim the space for its
>> intended purpose?
> You can reduce the size of metadata this way:
> (It might be in future automated somehow in LV - as there
> are further enhancements on thin tools which can make 'reduction' of 
> -tmeta size a 'wanted' feature)
> For now you need to active thin-pool metadata in read-only mode (so 
> called 'component activation' (which means no thin-pool nor any thinLV 
> is active - only _tmeta LV and it's supported with some recent versions 
> of lvm)
> (For older version of lvm2 - you would need to first 'swap-out' existing 
> metadata to get access to them)
> Then create some 15GiB sized LV� (used as your rightly sized new metadata)
> Then run from 2.2T -> 15G LV:
>  �thin_repair� -i /dev/vg/pool_tmeta -o /dev/vg/newtmeta
> This might take some time (depending on CPU speed and disk speed) - and 
> also be sure you have� >= 0.8.5 of thin_repair tool (do not try this 
> with older version...)
> Once this thin_repair is finished - swap in your new tmeta LV:
> lvconvert --thinpool vg/pool --poolmetadata vg/newtmeta
> And now try to active your thinLVs and check all works.
> If all is ok - then you can 'lvremove' now unused� 2.2TiB LV� (with the 
> name newtmeta -� as� LV content has been swapped - just check with 'lvs 
> -a' output
> the sizes are whan you are expecting.
> If you are unsure with any step - consult further here your issue please
> (better before you do some irreversible mistake).
>> Currently I have no extends left - all eaten up by the metadata LV, but
>> I would be able to add another drive to enlargen the md raid and
>> therefore the PV/VG
> You will certainly need at least temporarily some extra space of ~15GiB.
> You can try with i.e. USB attached drive - you add such PV into VG 
> (vgextend)
> You then create your LV for new tmeta (as described above)
> Once you are happy with 'repaired'� thin-pool and your 2.2TiB LV is 
> removed,
> then you just 'pvmove' your new tmeta into VG on 'old' storage,
> And finally you will simply vgreduce your (now again) unused USB drive.
> Hopefully this will work well.
> Regards
> Zdenek

  parent reply	other threads:[~2020-01-10 16:30 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-02 18:19 [linux-lvm] thinpool metadata got way too large, how to handle? Ede Wolf
2020-01-08 11:29 ` Zdenek Kabelac
2020-01-08 14:23   ` Ede Wolf
2020-01-10 16:30   ` Ede Wolf [this message]
2020-01-10 16:51     ` Zdenek Kabelac

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