Hi, >>I have a last question though - is the kernel rbd implementation going >>to be improved? or should we just forget about that and just use librbd? >From my tests, I have around same performance between both with kernel 4.0. with kernel 3.16 I had bad speed regression This is with 4k block. But I have read on the mailing that they are other regression with bigger block in kernel > 3.18 since blk_mq implementation. The only difference I see is that krbd use around twice less cpu than librbd. ----- Mail original ----- De: "Jacek Jarosiewicz" <jjarosiewicz@xxxxxxxxxxxxx> À: "Mark Nelson" <mnelson@xxxxxxxxxx>, "ceph-users" <ceph-users@xxxxxxxxxxxxxx> Envoyé: Lundi 22 Juin 2015 09:52:43 Objet: Re: [SOLVED] rbd performance issue - can't find bottleneck On 06/18/2015 12:23 PM, Mark Nelson wrote: > I'm just guessing, but because your read performance is slow as well, > you may multiple issues going on. The Intel 530 being slow at O_DSYNC > writes is one of them, but it's possible there is something else too. If > I were in your position I think I'd try to beg/borrw/steal a single DC > S3700 or even 520 (despite it's presumed lack of safety) and just see > how a single OSD cluster using it does on your setup before replacing > everything. > After some (much!) more testing I finally have the results I'd expect! :) Turns out we had two problems at once - first was the ssd (530 and the problem mentioned) and the second was my testing scenario - the mounted rbd is significantly slower than accessing it through librbd. We've decided to go ahead and buy DC S3770 ssds. So you were right all along. :) Thanks for the help - much appreciated! I have a last question though - is the kernel rbd implementation going to be improved? or should we just forget about that and just use librbd? Cheers, J -- Jacek Jarosiewicz Administrator Systemów Informatycznych ---------------------------------------------------------------------------------------- SUPERMEDIA Sp. z o.o. z siedzibą w Warszawie ul. Senatorska 13/15, 00-075 Warszawa Sąd Rejonowy dla m.st.Warszawy, XII Wydział Gospodarczy Krajowego Rejestru Sądowego, nr KRS 0000029537; kapitał zakładowy 42.756.000 zł NIP: 957-05-49-503 Adres korespondencyjny: ul. Jubilerska 10, 04-190 Warszawa ---------------------------------------------------------------------------------------- SUPERMEDIA -> http://www.supermedia.pl dostep do internetu - hosting - kolokacja - lacza - telefonia _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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