[DRBD-user] MySQL-over-DRBD Performance

Art Age Software artagesw at gmail.com
Sat Dec 15 20:24:49 CET 2007

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.

On Dec 15, 2007 3:20 AM, Lars Ellenberg <lars.ellenberg at linbit.com> wrote:

> > In my case, I am replacing a 3-year old pair of Dell 2850's (4GB,
> > Dual-Proc/Single-Core)  with a pair of new  Dell 2950's (8GB,
> > Dual-Proc/Quad-Core). Clearly, I expect to see an overall performance
> > boost from the new servers. And for most operations I am seeing better
> > performance. However for writes, I am seeing **worse** performance.
> > **But only when the database is located on the DRBD device.**
> you can try and pin drbd threads (using taskset) as well as the interrupt
> handler for your NIC (/proc/interrupts, proc/irq/<nr>/smp_affinity)
> to one dedicated cpu, and see if that changes things.
> it used to help in similar weird cases.

This is a bit over my head - but I will look into it.

> you can also verify wether the network bonding introduces additional latency.

Yes, I was planning to investigate this further. But since performance
of the resync was fine, it did not seem that bonding was causing any

What  write performance overhead should I expect from DRBD in a
configuration like mine? (And thanks for the suggestions.)


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