From mboxrd@z Thu Jan 1 00:00:00 1970 References: <76b114ca-404b-d7e5-8f59-26336acaadcf@assyoma.it> <0c6c96790329aec2e75505eaf544bade@assyoma.it> <8fee43a1-dd57-f0a5-c9de-8bf74f16afb0@gmail.com> <872ad7be3b36e2eb0afc080fa781d84d@assyoma.it> From: Gionatan Danti Message-ID: <0ef779b9-1725-4764-0664-0002344532dd@assyoma.it> Date: Tue, 12 Sep 2017 18:57:21 +0200 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [linux-lvm] Reserve space for specific thin logical volumes Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Zdenek Kabelac , LVM general discussion and development On 12/09/2017 14:03, Zdenek Kabelac wrote:> # lvs -a > LV VG Attr LSize Pool Origin Data% Meta% Move > Log Cpy%Sync Convert > [lvol0_pmspare] vg ewi------- 2,00m > lvol1 vg Vwi-a-tz-- 20,00m pool 40,00 > pool vg twi-aotz-- 10,00m 80,00 1,95 > [pool_tdata] vg Twi-ao---- 10,00m > [pool_tmeta] vg ewi-ao---- 2,00m > [root@linux export]# lvcreate -V10 vg/pool > Using default stripesize 64,00 KiB. > Reducing requested stripe size 64,00 KiB to maximum, physical extent > size 32,00 KiB. > Cannot create new thin volume, free space in thin pool vg/pool > reached threshold. > > # lvcreate -s vg/lvol1 > Using default stripesize 64,00 KiB. > Reducing requested stripe size 64,00 KiB to maximum, physical extent > size 32,00 KiB. > Cannot create new thin volume, free space in thin pool vg/pool > reached threshold. > > # grep thin_pool_autoextend_threshold /etc/lvm/lvm.conf > # Configuration option activation/thin_pool_autoextend_threshold. > # thin_pool_autoextend_threshold = 70 > thin_pool_autoextend_threshold = 70 > > So as you can see - lvm2 clearly prohibits you to create a new thinLV > when you are above defined threshold. Hi Zdenek, this is very good news (for me at least). Thank you very much for pointing me that! Anyway, I can not find the relative configuration variable in lvm.conf. I am on 2.02.166(2)-RHEL7, should I use a newer LVM version to set this threshold? > To keep things single for a user - we have a single threshold value. > > > So what else is missing ? This is a very good step, indeed. However, multiple threshold (maybe attached/counted against the single thin volume, in a manner similar to how refreservation does for ZVOLs) would be even better (in my use case, at least). > Unfortunatelly lvm2 nor dm can be responsible for whole kernel logic and > all user-land apps... Again, I am *not* saying, nor asking, that. I would simply like to use thinp without fearing that "forgotten" snapshot fill up the thin pool. I have shown how this can easily achieved with ZVOLs and careful use/setting of the refreservation value, without any upper layer knowledge and/or intra-layer communications. > So you are already happy right :) ? Sure! :) Thanks. -- Danti Gionatan Supporto Tecnico Assyoma S.r.l. - www.assyoma.it email: g.danti@assyoma.it - info@assyoma.it GPG public key ID: FF5F32A8