[linux-lvm] Reserve space for specific thin logical volumes

Zdenek Kabelac zkabelac at redhat.com
Wed Sep 13 19:17:48 UTC 2017

Dne 13.9.2017 v 19:41 Xen napsal(a):
> Zdenek Kabelac schreef op 12-09-2017 23:57:
>> Users interested in thin-provisioning are really mostly interested in
>> performance - especially on multicore machines with lots of fast
>> storage with high IOPS throughput  (some of them even expect it should
>> be at least as good as linear....)
> Why don't you hold a survey?
> And not phrase it in terms of "Would you like to sacrifice performance for 
> more safety?"
> But please.
> Ask people:
>> Repeated again - whoever targets for 100% full thin-pool usage has
>> misunderstood purpose of thin-provisioning.....
> Again, no one "targets" for 100% full. It is just an eventuality we need to 
> take care of.
> You design for failure.

Thin-pool IS designed for failure - who said it isn't ?

It has very matured protection against data corruption.

It's just not getting  overcomplicated in-kernel - solution is left for the 
user-space - that's very clear design of 'dm' for decades...

> If I was a customer and I was paying your bills, you would never respond like 
> this.

We are very nice to customers which pays our bills....

> We like to design in advance so we do not have to keep a constant eye out.

Please if you can show the case where the current upstream thinLV fails and 
you lose your data - we can finally start to fix something.

I'm still unsure what problem you want to get resolved from pretty small group 
of people around dm/lvm2 - do you want from us to rework kernel page-cache ?

I'm simply still confused what kind action you expect...

Be specific with real world example.



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