Re: recent osd changes

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On Wed, 19 Jun 2013, John Nielsen wrote:
> Thanks for the update (and, as always, the great work)!
> 
> Could you also indicate for each change which development and stable release(s) they (will) appear in?

Sure!

> On Jun 19, 2013, at 2:04 PM, Sage Weil <sage@xxxxxxxxxxx> wrote:
> > The OSDs used to only heartbeat on teh cluster interface.  Since they 
> > actually talk to clients on the public interface this didn't detect 
> > certain assymetrical network failures; this was fixed in the last release.
> > 
> > We also fixed a long-standing isue where the failure of the backend 
> > network would cause an OSD to be marked down, but it would mark itself 
> > back up by talking to the mon on the public interface.  It now verifies 
> > that the backend network is working (by pinging random other osds) before 
> > marking itself back up to avoid the problem.

This will land in v0.65 (out next week).

> > The last change was a more robust writeback model.  We have a general 
> > problem where we are journaling writes and then applying them to the file 
> > system, but the two devices/targets may go at different speeds.  We don't 
> > want to journal to get too far ahead of the fs or else request latency 
> > become erratic/bursty and the eventual fs commit can take a very long 
> > time.  Sam put togther a simple model of how much work the fs has pending 
> > for the next commit (based on dirty bytes, dirty files, dirty inodes) and 
> > bases throttling decisions on that instead of the very rough limits that 
> > used to be in place.  This resolves many 'slow request' warnings and even 
> > OSD failures (due to op_tp timeouts from very deep queues) on certain 
> > torturous workload (ffsb).

Also v0.65
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