From: Xen <list@xenhideout.nl>
To: linux-lvm@redhat.com
Subject: Re: [linux-lvm] Reserve space for specific thin logical volumes
Date: Wed, 20 Sep 2017 15:05:06 +0200 [thread overview]
Message-ID: <e313e53f07abafead1713f03cf179542@xenhideout.nl> (raw)
In-Reply-To: <d4b39ca6a299eb609f27f99e24eb7e26@assyoma.it>
Gionatan Danti schreef op 18-09-2017 21:20:
> Xen, I really think that the combination of hard-threshold obtained by
> setting thin_pool_autoextend_threshold and thin_command hook for
> user-defined script should be sufficient to prevent and/or react to
> full thin pools.
I will hopefully respond to Zdenek's message later (and the one before
that that I haven't responded to),
> I'm all for the "keep it simple" on the kernel side.
But I don't mind if you focus on this,
> That said, I would like to see some pre-defined scripts to easily
> manage pool fullness. (...) but I would really
> like the standardisation such predefined scripts imply.
And only provide scripts instead of kernel features.
Again, the reason I am also focussing on the kernel is because:
a) I am not convinced it cannot be done in the kernel
b) A kernel feature would make space reservation very 'standardized'.
Now I'm not convinced I really do want a kernel feature but saying it
isn't possible I think is false.
The point is that kernel features make it much easier to standardize and
to put some space reservation metric in userland code (it becomes a
default feature) and scripts remain a little bit off to the side.
However if we *can* standardize on some tag or way of _reserving_ this
space, I'm all for it.
I think a 'critical' tag in combination with the standard
autoextend_threshold (or something similar) is too loose and ill-defined
and not very meaningful.
In other words you would be abusing one feature for another purpose.
So I do propose a way to tag volumes with a space reservation (turning
them cricical) or alternatively to configure a percentage of reserved
space and then merely tag some volumes as critical volumes.
I just want these scripts to be such that you don't really need to
modify them.
In other words: values configured elsewhere.
If you think that should be the thin_pool_autoextend_threshold, fine,
but I really think it should be configured elsewhere (because you are
not using it for autoextending in this case).
thin_command is run every 5%:
https://www.mankier.com/8/dmeventd
You will need to configure a value to check against.
This is either going to be a single, manually configured, fixed value
(in % or extents)
Or it can be calculated based on reserved space of individual volumes.
So if you are going to have a kind of "fsfreeze" script based on
critical volumes vs. non-critical volumes I'm just saying it would be
preferable to set the threshold at which to take action in another way
than by using the autoextend_threshold for that.
And I would prefer to set individual space reservation for each volume
even if it can only be compared to 5% threshold values.
So again: if you want to focus on scripts, fine.
next prev parent reply other threads:[~2017-09-20 13:05 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
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 [this message]
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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