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