On 21/05/2013, at 21.00, Samuel Just <sam.just@xxxxxxxxxxx> wrote: > How large are the xattrs? > -Sam Sam, They are quite small, as far as I can see from 10-50 chars each. However, as you just explained on irc, our current unbounded 1:1 files vs. objects aproach, which in rare cases leads to ~25GB large objects, is not a good idea.. Could those large objects be what triggers the large leveldb allocation (and eventuelly the segfault)? -- Anders > On Tue, May 21, 2013 at 10:13 AM, Emil Renner Berthing <ceph@xxxxxxxx> wrote: >> On 21 May 2013 19:05, Samuel Just <sam.just@xxxxxxxxxxx> wrote: >>> Do you use xattrs at all? >> >> Yes, on each object we set between 2 to 4 attributes at write time >> which are then left unchanged. >> /Emil >> >>> -Sam >>> >>> On Tue, May 21, 2013 at 9:34 AM, Anders Saaby <anders@xxxxxxxxx> wrote: >>>> On 21/05/2013, at 18.19, Gregory Farnum <greg@xxxxxxxxxxx> wrote: >>>>> On Tue, May 21, 2013 at 9:01 AM, Emil Renner Berthing <ceph@xxxxxxxx> wrote: >>>>>> On 21 May 2013 17:55, Gregory Farnum <greg@xxxxxxxxxxx> wrote: >>>>>>> On Tue, May 21, 2013 at 8:44 AM, Emil Renner Berthing <ceph@xxxxxxxx> wrote: >>>>>>>> Hi Greg, >>>>>>>> >>>>>>>> Here are some more stats on our servers: >>>>>>>> - each server has 64GB ram, >>>>>>>> - there are 12 OSDs pr. server, >>>>>>>> - each OSD uses around 1.5 GB of memory, >>>>>>>> - we have 18432 PGs, >>>>>>>> - around 5 to 10 MB writes/s is written to each OSD and almost no reads (yet). >>>>>>> >>>>>>> What interface are you writing with? How many OSD servers are there? >>>>>> >>>>>> We're using librados and there are 132 OSDs so far. >>>>> >>>>> Okay, so the allocation is happening in the depths of LevelDB — maybe >>>>> the issue is there somewhere. Are you doing anything weird with omap, >>>>> snapshots, or xattrs? >>>> >>>> I can help; No, we are not using omap, snaps or weird stuff with xattrs. >>>> >>>> We are storing objects of sizes from few KB to GBs. Also, we have a quirk in the application design right now, which means that we store an object, write it again under a new name and delete the original object. - if that is of any potential value to finding this. >>>> >>>> >>>> -- >>>> Anders -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
