Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.
On Tue, 17 Jun 2008, William Francis wrote: > > I upgraded my drbd kernel module and userland tools to 8.0.12 and added the > two additional parameters to my disk section of my drbd.conf as Lee > suggested and wow, a full 10X improvement in write speed, which is about 60% > of bare metal speed. > > What does this suggest? Does 8.0.11 have some performance ....um, issues (or (my bad, I sent this from an unsubscribed address, hopefully it will not show up twice...) this has all been covered on the list... Date: Sat, 24 May 2008 21:35:10 +0200 From: Philipp Reisner <philipp.reisner at linbit.com> To: drbd-user at linbit.com Subject: Re: [DRBD-user] 8.x performance vs 0.7x --- was (not urgent) Request for DRBD Developers [...] > > > Personally, I'm still on 8.0.8. Later versions at the time seemed to > > > show _VASTLY_ reduced performance on my hardware, so I excluded it > > > from > > > the updates. I'm not experiencing any problems, so I'm sticking with > > > it. That is due to that change: 8.0.9 (api:86/proto:86) -------- * In case our backing devices support write barriers and cache flushes, we use these means to ensure data integrity in the presence of volatile disk write caches and power outages. [...] 8.0.12 (api:86/proto:86) -------- [...] * Two new config options no-disk-flushes and no-md-flushes to disable the use of io subsystem flushes and barrier BIOs. [...] But please *read* the documentation about "no-disk-flushes" and understand the implications before you set these options. # In case you are sure that your storage subsystem has battery # backed up RAM and you know from measurements that it really honors # flush instructions by flushing data out from its non volatile # write cache to disk, you have double security. You might then # reduce this to single security by disabling disk flushes with # this option. It might improve performance in this case. # ONLY USE THIS OPTION IF YOU KNOW WHAT YOU ARE DOING. # no-disk-flushes; # no-md-flushes; -Phil _______________________________________________ drbd-user mailing list drbd-user at lists.linbit.com http://lists.linbit.com/mailman/listinfo/drbd-user