[Users] HDD and SSD for OpenVZ legagy

[Andrey Tataranovich]

On Fri, 12 Feb 2016 15:01:14 +0300
Andrey Tataranovich <tataranovich at gmail.com> wrote:

> On Wed, 10 Feb 2016 21:05:23 +0100
> Volker Janzen <voja at voja.de> wrote:
> 
> > if my server for OpenVZ legacy has HDD and SSD, what can I do to
> > benefit from SSD speed?
> 
> Recently I have tested following solutions for openvz legacy server:
> 
>  * flashcache 3.1.2 (writeback mode)
>  * btier 1.3.11
>  * dm-cache (bundled in openvz kernel)
> 
> Not tested btier 2.x, bcache and enhanceio due to minimal kernel
> version requirements.
> 
> In my tests flashcache was the fastest when measuring random IO (iops,
> latency and bandwidth).
> 

Using flashcache/dm-cache you do not need to prepare you existing data.
Unmount /vz, create SSD cache device, and mount cache device to /vz.

Do not use LABEL or UUID in fstab on this stage to avoid mounting cache
backend device!

Btier cannot use existing data.

-- 
WBR, Andrey Tataranovich