On Thu, Jan 15, 2015 at 2:44 PM, Michael Sevilla <[email protected]> wrote: > Let me know if this works and/or you need anything else: > > https://www.dropbox.com/s/fq47w6jebnyluu0/lookup-logs.tar.gz?dl=0 > > Beware - the clients were on debug=10. Also, I tried this with the > kernel client and it is more consistent; it does the 2 lookups per > create on 1 client every single time.
Mmmm, there are no mds logs of note here. :( I did look enough to see that: 1) The MDS is for some reason revoking caps on the file create prompting the switch to double-lookups, which it was not before. The client doesn't really have any visibility into why that would be the case; the best guess I can come up with is that maybe the MDS split up the directory into multiple frags at this point — do you have that enabled? 2) The only way we set the I_COMPLETE flag is when we create an empty directory, or when we do a complete listdir on one. That makes it pretty difficult to get the flag back (and so do the optimal create path) once you lose it. :( I'd love a better way to do so, but we'll have to look at what's involved in a bit of depth. I'm not sure why the kernel client is so much more cautious, but I think there were a number of troubles with the directory listing orders and things which were harder to solve there – I don't remember if we introduced the I_DIR_ORDERED flag in it or not. Zheng can talk more about that. What kernel client version are you using? And for a vanity data point, what kind of hardware is your MDS running on? :) -Greg -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
