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

Xen list at xenhideout.nl
Tue Sep 12 16:49:56 UTC 2017

Zdenek Kabelac schreef op 12-09-2017 16:57:

> This bug has been reported (by me even to libblkid maintainer) AND
> already fixed already in past....

I was the one who reported it.

This was Karel Zak's message from 30 august 2016:

"On Fri, Aug 19, 2016 at 01:14:29PM +0200, Karel Zak wrote:
On Thu, Aug 18, 2016 at 10:39:30PM +0200, Xen wrote:
Would someone be will to fix the issue that a Physical Volume from LVM2 
when placed directly on disk (no partitions or partition tables) will 
not be

This is very unusual setup, but according to feedback from LVM guys
it's supported, so I will improve blkid to support it too.

Fixed in the git tree (for the next v2.29). Thanks.


So yes, I knew what I was talking about.

At least slightly ;-).


> But to defend a bit libblkid maintainer side :) - this feature was not
> really well documented from lvm2 side...

That's fine.

>>> You can sync every second to minimize amount of dirty pages....
>>> Lots of things....  all of them will in some other the other impact
>>> system performance....
>> He said no people would be hurt by such a measure except people who 
>> wanted to unpack and compile kernel pure in page buffers ;-).
> So clearly you need to spend resources effectively and support both 
> groups...
> Sometimes is better to use large RAM (common laptops have 32G of RAM 
> nowadays)

Yes and he said those people wanting to compile the kernel purely in 
memory (without using RAM disk for it) have issues anyway...


So no it is not that clear that you need to support both groups. 
Certainly not by default.

Or at least not in its default configuration for some dirty page file 
flag ;-).

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