[linux-lvm] Why use thin_pool_autoextend_threshold < 100 ?

2018-07-26 Thread Marc MERLIN
Still learning about thin volumes. Why do I want my thin pool to get auto extended? Does "extended" mean resized? Why would I want to have thin_pool_autoextend_threshold below 100 and have it auto extend as needed vs having all of them be at 100, knowing that underlying block allocation will fail

Re: [linux-lvm] Can't create thin lv

2018-07-26 Thread Marc MERLIN
On Thu, Jul 26, 2018 at 10:40:42AM +0200, Zdenek Kabelac wrote: > What are you trying to achieve with 'mkdir /dev/vgds2/' ? > You shall never ever touch /dev content - it's always under full control > of udev - if you start to create there your own files and directories you > will break whole usa

Re: [linux-lvm] Trying to understand format of LVM2 - Question on Extent Size

2018-07-26 Thread Zdenek Kabelac
Dne 26.7.2018 v 06:25 David F. napsal(a): Never mind, the answer is the extent_size is the number of sectors (or perhaps it's the number of 512 byte blocks, I'll have to test on 4K sector drives). So in this case 4M and 4M*3840 is the 16G (not 16M which was the 3840*4096). On Wed, Jul 25,

Re: [linux-lvm] Can't create thin lv

2018-07-26 Thread Zdenek Kabelac
Dne 26.7.2018 v 09:24 Marc MERLIN napsal(a): On Wed, Jul 25, 2018 at 05:41:54PM -0700, Marc MERLIN wrote: Howdy, Kernel 4.17, trying thin LV for the first time, and I'm getting this: gargamel:~# lvcreate -L 14.50TiB -Zn -T vgds2/thinpool2 Using default stripesize 64.00 KiB. Thin pool volu

Re: [linux-lvm] Trying to understand format of LVM2 - Question on Extent Size

2018-07-26 Thread David F.
Never mind, the answer is the extent_size is the number of sectors (or perhaps it's the number of 512 byte blocks, I'll have to test on 4K sector drives). So in this case 4M and 4M*3840 is the 16G (not 16M which was the 3840*4096). On Wed, Jul 25, 2018 at 5:37 PM, David F. wrote: > I created

[linux-lvm] Trying to understand format of LVM2 - Question on Extent Size

2018-07-26 Thread David F.
I created a test lvm on a 32G UFD with two logical volumes, 15G and 14G. I then looked at the on disk data and most makes since except the extent_count vs extent_size. In this case the extent_size is 8192, and it says the extent sizes are 3840 and 3584, but that * 8192 is double its actual size.

Re: [linux-lvm] Can't create thin lv

2018-07-26 Thread Marc MERLIN
On Wed, Jul 25, 2018 at 05:41:54PM -0700, Marc MERLIN wrote: > Howdy, > > Kernel 4.17, trying thin LV for the first time, and I'm getting this: > gargamel:~# lvcreate -L 14.50TiB -Zn -T vgds2/thinpool2 > Using default stripesize 64.00 KiB. > Thin pool volume with chunk size 8.00 MiB can addre