From: Zdenek Kabelac <zkabelac@redhat.com>
To: linux-lvm@redhat.com
Subject: Re: [linux-lvm] Reserve space for specific thin logical volumes
Date: Mon, 11 Sep 2017 13:20:51 +0200 [thread overview]
Message-ID: <6e9535b6-218c-3f66-2048-88e1fcd21329@redhat.com> (raw)
In-Reply-To: <7d0d218c420d7c687d1a17342da5ca00@xenhideout.nl>
Dne 11.9.2017 v 12:55 Xen napsal(a):
> Zdenek Kabelac schreef op 11-09-2017 12:35:
>
>> As thin-provisioning is about 'promising the space you can deliver
>> later when needed'� - it's not about hidden magic to make the space
>> out-of-nowhere.
>> The idea of planning to operate thin-pool on 100% fullness boundary is
>> simply not going to work well - it's� not been designed for that
>> use-case
>
> I am going to rear my head again and say that a great many people would
> probably want a thin-provisioning that does exactly that ;-).
>
Wondering from where they could get this idea...
We always communicate clearly - do not plan to use 100% full unresizable
thin-pool as a part of regular work-flow - it's always critical situation
often even leading to system's reboot and full check of all volumes.
> I mean you have it designed for auto-extension but there are also many people
> that do not want to auto-extend and just share available resources more flexibly.
>
> For those people safety around 100% fullness boundary becomes more important.
>
> I don't really think there is another solution for that.
>
> I don't think BTRFS is really a good solution for that.
>
> So what alternatives are there, Zdenek? LVM is really the only thing that
> feels "good" to us.
>
Thin-pool needs to be ACTIVELY monitored and proactively either added more PV
free space to the VG or eliminating unneeded 'existing' provisioned blocks
(fstrim, dropping snapshots, removal of unneeded thinLVs.... - whatever
comes on your mind to make a more free space in thin-pool - lvm2 fully
supports now to call 'smart' scripts directly out of dmeventd for such action.
It's illusion to hope anyone will be able to operate lvm2 thin-pool at 100%
fullness reliable - there should be always enough room to give 'scripts'
reaction time to gain some more space in-time - so thin-pool can serve free
chunks for provisioning - that's been design - to deliver blocks when needed,
not to brake system
> Are there structural design inhibitions that would really prevent this thing
> from ever arising?
Yes, performance and resources consumption.... :)
And there is fundamental difference between full 'block device' sharing
space with other device - compared with single full filesystem - you can't
compare these 2 things at all.....
Regards
Zdenek
next prev parent reply other threads:[~2017-09-11 11:20 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-08 10:35 [linux-lvm] Reserve space for specific thin logical volumes Gionatan Danti
2017-09-08 11:06 ` Xen
2017-09-09 22:04 ` Gionatan Danti
2017-09-11 10:35 ` Zdenek Kabelac
2017-09-11 10:55 ` Xen
2017-09-11 11:20 ` Zdenek Kabelac [this message]
2017-09-11 12:06 ` Xen
2017-09-11 12:45 ` Xen
2017-09-11 13:11 ` Zdenek Kabelac
2017-09-11 13:46 ` Xen
2017-09-12 11:46 ` Zdenek Kabelac
2017-09-12 12:37 ` Xen
2017-09-12 14:37 ` Zdenek Kabelac
2017-09-12 16:44 ` Xen
2017-09-12 17:14 ` Gionatan Danti
2017-09-12 21:57 ` Zdenek Kabelac
2017-09-13 17:41 ` Xen
2017-09-13 19:17 ` Zdenek Kabelac
2017-09-14 3:19 ` Xen
2017-09-12 17:00 ` Gionatan Danti
2017-09-12 23:25 ` Brassow Jonathan
2017-09-13 8:15 ` Gionatan Danti
2017-09-13 8:33 ` Zdenek Kabelac
2017-09-13 18:43 ` Xen
2017-09-13 19:35 ` Zdenek Kabelac
2017-09-14 5:59 ` Xen
2017-09-14 19:05 ` Zdenek Kabelac
2017-09-15 2:06 ` Brassow Jonathan
2017-09-15 6:02 ` Gionatan Danti
2017-09-15 8:37 ` Xen
2017-09-15 7:34 ` Xen
2017-09-15 9:22 ` Zdenek Kabelac
2017-09-16 22:33 ` Xen
2017-09-17 6:31 ` Xen
2017-09-17 7:10 ` Xen
2017-09-18 19:20 ` Gionatan Danti
2017-09-20 13:05 ` Xen
2017-09-21 9:49 ` Zdenek Kabelac
2017-09-21 10:22 ` Xen
2017-09-21 13:02 ` Zdenek Kabelac
2017-09-21 14:34 ` [linux-lvm] Clarification (and limitation) of the kernel feature I proposed Xen
2017-09-21 14:49 ` [linux-lvm] Reserve space for specific thin logical volumes Xen
2017-09-21 20:32 ` Zdenek Kabelac
2017-09-18 8:56 ` Zdenek Kabelac
2017-09-11 14:00 ` Xen
2017-09-11 17:34 ` Zdenek Kabelac
2017-09-11 15:31 ` Eric Ren
2017-09-11 15:52 ` Zdenek Kabelac
2017-09-11 21:35 ` Eric Ren
2017-09-11 17:41 ` David Teigland
2017-09-11 21:08 ` Eric Ren
2017-09-11 16:55 ` David Teigland
2017-09-11 17:43 ` Zdenek Kabelac
2017-09-11 21:59 ` Gionatan Danti
2017-09-12 11:01 ` Zdenek Kabelac
2017-09-12 11:34 ` Gionatan Danti
2017-09-12 12:03 ` Zdenek Kabelac
2017-09-12 12:47 ` Xen
2017-09-12 13:51 ` pattonme
2017-09-12 14:57 ` Zdenek Kabelac
2017-09-12 16:49 ` Xen
2017-09-12 16:57 ` Gionatan Danti
[not found] <832949972.1610294.1505170613541.ref@mail.yahoo.com>
2017-09-11 22:56 ` matthew patton
2017-09-12 5:28 ` Gionatan Danti
[not found] <1806055156.426333.1505228581063.ref@mail.yahoo.com>
2017-09-12 15:03 ` matthew patton
2017-09-12 17:09 ` Gionatan Danti
2017-09-12 22:41 ` Zdenek Kabelac
2017-09-12 22:55 ` Gionatan Danti
2017-09-12 23:11 ` Zdenek Kabelac
[not found] <418002318.647314.1505245480415.ref@mail.yahoo.com>
[not found] ` <418002318.647314.1505245480415@mail.yahoo.com>
2017-09-12 21:36 ` Gionatan Danti
2017-09-12 22:16 ` Zdenek Kabelac
2017-09-12 22:41 ` Gionatan Danti
2017-09-12 23:02 ` Zdenek Kabelac
2017-09-12 23:15 ` Gionatan Danti
2017-09-12 23:31 ` Zdenek Kabelac
2017-09-13 8:21 ` Gionatan Danti
[not found] <1575245610.821680.1505258554456.ref@mail.yahoo.com>
2017-09-12 23:22 ` matthew patton
2017-09-13 7:53 ` Gionatan Danti
2017-09-13 8:15 ` Zdenek Kabelac
2017-09-13 8:28 ` Gionatan Danti
2017-09-13 8:44 ` Zdenek Kabelac
2017-09-13 10:46 ` Gionatan Danti
[not found] <691633892.829188.1505258696384.ref@mail.yahoo.com>
2017-09-12 23:24 ` matthew patton
[not found] <57374453.843393.1505261050977.ref@mail.yahoo.com>
2017-09-13 0:04 ` matthew patton
2017-09-13 7:10 ` Zdenek Kabelac
[not found] <1771452279.913055.1505269434212.ref@mail.yahoo.com>
2017-09-13 2:23 ` matthew patton
2017-09-13 7:25 ` Zdenek Kabelac
[not found] <498090067.1559855.1505338608244.ref@mail.yahoo.com>
2017-09-13 21:36 ` matthew patton
[not found] <914479528.2618507.1505463313888.ref@mail.yahoo.com>
2017-09-15 8:15 ` matthew patton
2017-09-15 10:01 ` Zdenek Kabelac
2017-09-15 18:35 ` Xen
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