Hi Nikolas,

Zitat von Nikolaus Rath [off-list ref]:

[...]
Indeed. But it's also yet another slightly worrying tidbit (maybe LVM is
not considering it by default for a good reason).

Agreed, but from what I read, newer versions of LVM were said to  
support bcache devices out of the box  
(https://www.redhat.com/archives/linux-lvm/2012-March/msg00007.html).

Also, just now someone on -btrfs advised:

| > Otherwise I'll give bcache a shot. I've avoided it so far because of the
| > need to reformat and because of rumours that it doesn't work well with
| > LVM or BTRFS. But it sounds as if that's not the case..
|
| It should work fine with _just_ BTRFS, but don't put any other layers
| into the storage system like LVM or dmcrypt or mdraid, it's got some
| pretty pathological interactions with the device mapper and md
| frameworks still.

It might be that this is a bit oldish info. BTW, I read that BTRFS on  
LVM is bad and causes problems ;)

We run MD-RAID (R6 for HDDs, R1 for SSDs) beneath bcache. We've run  
thousands of Gigabytes of read and write traffic through this,  
successfully. (And of course - YMMV :-/ ). We've used SATA disks  
(RAID-compatible WD Red) & SSDs (when not running via Supermicro's  
servers with SAS Extender chassis) and SAS disks & SSDs (on those  
servers with SAS extender), all fine.

 From my point of view, bcache with latest bug fixes is a helpful and  
(operationally) stable solution.

Regards,
Jens