Re: [linux-lvm] lvmcache writethrough synchronisation at system startup

[Zdenek Kabelac <zkabelac@redhat.com>]

Dne 05. 12. 18 v 16:01 Marcin Wolcendorf napsal(a):
> Hi,
> 
> Thanks for your reply!
> 
> On Wed, Dec 05, 2018 at 03:23:21PM +0100, Zdenek Kabelac wrote:
>> Dne 05. 12. 18 v 7:19 Marcin Wolcendorf napsal(a):
>>> My setup:
>>> I have 2 mdraid devices: one 24T raid6, one 1T raid1, and one separate SSD. All
>>> are LUKS-encrypted, SSD is partitioned into MBR boot partition, encrypted /boot
>>> partition and a big encrypted partition for a PV. The encrypted block devices
>>> (except /boot) are PVs in my VG. The 24T RAID holds the origin LV, the 1T RAID
>>> is made into a cachepool.
>>
>> Hi
>>
>> I'd say in your case it's very important which version of kernel is in use,
>> as there very couple fixes solving this issue in not too long history.
> 
> $ uname -a
> Linux hal-9002 4.18.0-2-amd64 #1 SMP Debian 4.18.10-2 (2018-11-02) x86_64 GNU/Linux
> 
> I think it's not *that* old.
> I searched for some info about this issue, but my google mojo left me and I
> didn't find anything. Can you point me to some place - like commit or bug
> description - where I could read about those fixes?
> 
>> Secondary issue is - it's always good idea there is correct shutdown process
>> instead of just 'power-off' althouhg in 'writethrough' case it should not be
>> that big issue (but here applies the advice number one - use recent
>> kernels).
> 
> OK, so how should the shutdown look like?
> 


On i.e. Fedora distribution all filesystems are unmounted and all LVs are 
deactivatated -  due to switch to shutdown 'ramdisk' (reusing the one from 
initial boot).


Zdenek