From mboxrd@z Thu Jan 1 00:00:00 1970 From: Loic Dachary Subject: Re: ceph-disk improvements Date: Tue, 5 Apr 2016 12:21:41 +0200 Message-ID: <570391B5.1050207@dachary.org> References: <2041558235.2113.160e133c-ee3f-4c6e-9b8b-e4d468651d78.open-xchange@ox.pcextreme.nl> <1651492587.2194.160e133c-ee3f-4c6e-9b8b-e4d468651d78.open-xchange@ox.pcextreme.nl> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from relay5-d.mail.gandi.net ([217.70.183.197]:35261 "EHLO relay5-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756695AbcDEKVr (ORCPT ); Tue, 5 Apr 2016 06:21:47 -0400 In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Ilya Dryomov , Sebastien Han Cc: Wido den Hollander , Sage Weil , Ceph Development , Samuel Yaple Hi Ilya, On 05/04/2016 11:26, Ilya Dryomov wrote: > On Tue, Apr 5, 2016 at 10:30 AM, Sebastien Han wrot= e: >> Wido, I just discussed that with Sam last week and it seems that >> bcache allocates a minor of 1 when creating the device. >> Sam ended up writing this: >> https://yaple.net/2016/03/31/bcache-partitions-and-dkms/ >> The fix is not complex not sure why it is not part of bcache yet... >=20 > I think it's just that no one complained loud enough. >=20 >> >> Not sure if it's ceph-disk's job to do all of this with bcache thoug= h... >> We might need to check with the bache guys what are their plans abou= t this. >> If this will go through at some point we might just wait, if not we >> could implement the partition trick on ceph-disk. >=20 > Making something like this go through shouldn't be a problem. Sam's > patch is a bit of quick hack though - it messes up bcache device IDs > and also limits the number of partitions to 16. Better to avoid > another hard-coded constant, if possible. >=20 > # ls -lh /dev/bcache* > brw-rw---- 1 root disk 254, 0 Mar 31 20:17 /dev/bcache0 > brw-rw---- 1 root disk 254, 1 Mar 31 20:17 /dev/bcache0p1 > brw-rw---- 1 root disk 254, 16 Mar 31 20:17 /dev/bcache16 > brw-rw---- 1 root disk 254, 17 Mar 31 20:17 /dev/bcache16p1 > brw-rw---- 1 root disk 254, 32 Mar 31 20:17 /dev/bcache32 > brw-rw---- 1 root disk 254, 33 Mar 31 20:17 /dev/bcache32p1 >=20 > We had to solve almost exactly this problem in rbd. I can submit > a patch for bcache if it helps ceph-disk in the long run. It would help. Implementing a workaround in ceph-disk to compensate for= the fact that bcache does not support partitioning feels much better w= hen there is hope it will eventually be removed :-) Cheers >=20 > Thanks, >=20 > Ilya > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel"= in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >=20 --=20 Lo=C3=AFc Dachary, Artisan Logiciel Libre -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html