From: Zdenek Kabelac <zkabelac@redhat.com>
To: Xen <list@xenhideout.nl>
Cc: LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] Snapshot behavior on classic LVM vs ThinLVM
Date: Sat, 22 Apr 2017 23:17:42 +0200 [thread overview]
Message-ID: <6dd12ab9-0390-5c07-f4b7-de0d8fbbeacf@redhat.com> (raw)
In-Reply-To: <b1b73e21196be7c50daa098b2724880a@xenhideout.nl>
Dne 22.4.2017 v 18:32 Xen napsal(a):
> Gionatan Danti schreef op 22-04-2017 9:14:
>> Il 14-04-2017 10:24 Zdenek Kabelac ha scritto:
>>> However there are many different solutions for different problems -
>>> and with current script execution - user may build his own solution -
>>> i.e. call
>>> 'dmsetup remove -f' for running thin volumes - so all instances get
>>> 'error' device when pool is above some threshold setting (just like
>>> old 'snapshot' invalidation worked) - this way user will just kill
>>> thin volume user task, but will still keep thin-pool usable for easy
>>> maintenance.
>>>
>>
>> This is a very good idea - I tried it and it indeed works.
>
> So a user script can execute dmsetup remove -f on the thin pool?
>
> Oh no, for all volumes.
>
> That is awesome, that means a errors=remount-ro mount will cause a remount right?
Well 'remount-ro' will fail but you will not be able to read anything
from volume as well.
So as said - many users many different solutions are needed...
Currently lvm2 can't support that much variety and complexity...
>
>> However, it is not very clear to me what is the best method to monitor
>> the allocated space and trigger an appropriate user script (I
>> understand that versione > .169 has %checkpoint scripts, but current
>> RHEL 7.3 is on .166).
>>
>> I had the following ideas:
>> 1) monitor the syslog for the "WARNING pool is dd.dd% full" message;
>
> This is what my script is doing of course. It is a bit ugly and a bit messy by
> now, but I could still clean it up :p.
>
> However it does not follow syslog, but checks periodically. You can also
> follow with -f.
>
> It does not allow for user specified actions yet.
>
> In that case it would fulfill the same purpose as > 169 only a bit more poverly.
>
>> One more thing: from device-mapper docs (and indeed as observerd in my
>> tests), the "pool is dd.dd% full" message is raised one single time:
>> if a message is raised, the pool is emptied and refilled, no new
>> messages are generated. The only method I found to let the system
>> re-generate the message is to deactiveate and reactivate the thin pool
>> itself.
>
> This is not my experience on LVM 111 from Debian.
>
> For me new messages are generated when:
>
> - the pool reaches any threshold again
> - I remove and recreate any thin volume.
>
> Because my system regenerates snapshots, I now get an email from my script
> when the pool is > 80%, every day.
>
> So if I keep the pool above 80%, every day at 0:00 I get an email about it :p.
> Because syslog gets a new entry for it. This is why I know :p.
The explanation here is simple - when you create a new thinLV - there is
currently full suspend - and before 'suspend' pool is 'unmonitored'
after resume again monitored - and you get your warning logged again.
Zdenek
next prev parent reply other threads:[~2017-04-22 21:17 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-06 14:31 [linux-lvm] Snapshot behavior on classic LVM vs ThinLVM Gionatan Danti
2017-04-07 8:19 ` Mark Mielke
2017-04-07 9:12 ` Gionatan Danti
2017-04-07 13:50 ` L A Walsh
2017-04-07 16:33 ` Gionatan Danti
2017-04-13 12:59 ` Stuart Gathman
2017-04-13 13:52 ` Xen
2017-04-13 14:33 ` Zdenek Kabelac
2017-04-13 14:47 ` Xen
2017-04-13 15:29 ` Stuart Gathman
2017-04-13 15:43 ` Xen
2017-04-13 17:26 ` Stuart D. Gathman
2017-04-13 17:32 ` Stuart D. Gathman
2017-04-14 15:17 ` Xen
2017-04-14 7:27 ` Gionatan Danti
2017-04-14 7:23 ` Gionatan Danti
2017-04-14 15:23 ` Xen
2017-04-14 15:53 ` Gionatan Danti
2017-04-14 16:08 ` Stuart Gathman
2017-04-14 17:36 ` Xen
2017-04-14 18:59 ` Gionatan Danti
2017-04-14 19:20 ` Xen
2017-04-15 8:27 ` Xen
2017-04-15 23:35 ` Xen
2017-04-17 12:33 ` Xen
2017-04-15 21:22 ` Xen
2017-04-15 21:49 ` Xen
2017-04-15 21:48 ` Xen
2017-04-18 10:17 ` Zdenek Kabelac
2017-04-18 13:23 ` Gionatan Danti
2017-04-18 14:32 ` Stuart D. Gathman
2017-04-19 7:22 ` Xen
2017-04-07 22:24 ` Mark Mielke
2017-04-08 11:56 ` Gionatan Danti
2017-04-07 18:21 ` Tomas Dalebjörk
2017-04-13 10:20 ` Gionatan Danti
2017-04-13 12:41 ` Xen
2017-04-14 7:20 ` Gionatan Danti
2017-04-14 8:24 ` Zdenek Kabelac
2017-04-14 9:07 ` Gionatan Danti
2017-04-14 9:37 ` Zdenek Kabelac
2017-04-14 9:55 ` Gionatan Danti
2017-04-22 7:14 ` Gionatan Danti
2017-04-22 16:32 ` Xen
2017-04-22 20:58 ` Gionatan Danti
2017-04-22 21:17 ` Zdenek Kabelac [this message]
2017-04-23 5:29 ` Xen
2017-04-23 9:26 ` Zdenek Kabelac
2017-04-24 21:02 ` Xen
2017-04-24 21:59 ` Zdenek Kabelac
2017-04-26 7:26 ` Gionatan Danti
2017-04-26 7:42 ` Zdenek Kabelac
2017-04-26 8:10 ` Gionatan Danti
2017-04-26 11:23 ` Zdenek Kabelac
2017-04-26 13:37 ` Gionatan Danti
2017-04-26 14:33 ` Zdenek Kabelac
2017-04-26 16:37 ` Gionatan Danti
2017-04-26 18:32 ` Stuart Gathman
2017-04-26 19:24 ` Stuart Gathman
2017-05-02 11:00 ` Gionatan Danti
2017-05-12 13:02 ` Gionatan Danti
2017-05-12 13:42 ` Joe Thornber
2017-05-14 20:39 ` Gionatan Danti
2017-05-15 12:50 ` Zdenek Kabelac
2017-05-15 14:48 ` Gionatan Danti
2017-05-15 15:33 ` Zdenek Kabelac
2017-05-16 7:53 ` Gionatan Danti
2017-05-16 10:54 ` Zdenek Kabelac
2017-05-16 13:38 ` Gionatan Danti
2018-02-27 18:39 ` Xen
2018-02-28 9:26 ` Zdenek Kabelac
2018-02-28 19:07 ` Gionatan Danti
2018-02-28 21:43 ` Zdenek Kabelac
2018-03-01 7:14 ` Gionatan Danti
2018-03-01 8:31 ` Zdenek Kabelac
2018-03-01 9:43 ` Gianluca Cecchi
2018-03-01 11:10 ` Zdenek Kabelac
2018-03-01 9:52 ` Gionatan Danti
2018-03-01 11:23 ` Zdenek Kabelac
2018-03-01 12:48 ` Gionatan Danti
2018-03-01 16:00 ` Zdenek Kabelac
2018-03-01 16:26 ` Gionatan Danti
2018-03-03 18:32 ` Xen
2018-03-04 20:34 ` Zdenek Kabelac
2018-03-03 18:17 ` Xen
2018-03-04 20:53 ` Zdenek Kabelac
2018-03-05 9:42 ` Gionatan Danti
2018-03-05 10:18 ` Zdenek Kabelac
2018-03-05 14:27 ` Gionatan Danti
2018-03-03 17:52 ` Xen
2018-03-04 23:27 ` Zdenek Kabelac
2017-04-22 21:22 ` Zdenek Kabelac
2017-04-24 13:49 ` Gionatan Danti
2017-04-24 14:48 ` Zdenek Kabelac
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