[DRBD-user] 20TB cluster: 1 big drbd disk or multiple small ones?

[Matt Kereczman]

On 6/21/21 3:19 AM, Eric Robinson wrote:
> Suppose you’re building a cluster with 20TB of storage that will run
>  multiple instances of MySQL. Which is better, creating one big drbd
>  disk, or carving it up into multiple smaller ones?

Many small DRBD resources is likely better than one large resource in 
this case. With multiple resources you'll have independent failure 
domains as opposed to one large one. Also, each DRBD resource will get 
it's own set of processes (worker/sender/receiver/etc.) and network 
socket which will likely help with performance.

You could even use, "options { cpu-mask $mask; }", in your DRBD 
configurations to ensure each resource gets it's own CPU thread. Here is 
a link to the relevant section in the DRBD users guide:
https://linbit.com/drbd-user-guide/drbd-guide-9_0-en/#s-latency-tuning-cpu-mask

> 
> Also, any thoughts about a preferred filesystem for this scenario?
<snip>
Any journaling FS (xfs/ext4) mounted with noatime should be fine.

Best Regards,
Matt