[linux-lvm] what todo with broken cachedev?

[Brassow Jonathan]

On Aug 11, 2014, at 7:55 AM, Zdenek Kabelac wrote:

> Dne 9.8.2014 19:25, Oliver Rath napsal(a):
>> Hi list,
>> 
>> assuming a cached device mylv from /dev/sda1 with cachepool from
>> /dev/sdb1 (ssd i.e.):
>> 
>> If now the ssd crashes and the cachemode is "writethrough" i think,
>> there is no data loss for my lv's, right?
>> 
>> But then mylv runs without a cache device although the device is set in
>> metadata.
>> 
>> The command lvreduce cant remove the cache-attribut. vgreduce *could*
>> remove it, right? But only if there is no usage bei the cachepool-device
>> anymore.
>> 
>> Is there a solution for that?
> 
> 
> Cache support is still experimental - so please open bugzillas
> for your issues found on  bugzilla.redhat.com
> (if you are not using Fedora/RHEL - use Fedora Rawhide for your reports)
> 
> I assume your problem is likely related to still missing repair support
> for cached volumes.
> 
> You would need to use  cache utils  (cache_check, cache_repair, cache_dump...) to fix broken metadata.

Also, it would be nice when using "writethrough" to have the option of abandoning the cache - making it a normal LV again.  If there is no way to get the SSD back, there is probably no point in fixing.  Operation might have to be forced if "writeback".

 brassow