> Op 29 september 2016 om 16:09 schreef Emmanuel Florac <eflorac@xxxxxxxxxxxxxx>: > > > Le Wed, 28 Sep 2016 21:14:50 +0200 (CEST) > Wido den Hollander <wido@xxxxxxxx> écrivait: > > > In both cases Ceph wants to create partitions on all disks it uses. > > By adding bcache in between the performance can be boosted really > > well. Fast NVM-e SSDs with some large SATA drives vastly improve > > performance. > > > > Yes, you could use LVM in between, but that just adds more layers and > > is rather complex to accomplish with the current tooling. If bcache > > would support partitions it would all be a lot easier. > > > > And next to Ceph there might be other tools which can benefit from > > partitions on bcache, who knows? > > Two points: first I'm pretty sure LVM is the preferred method nowadays > to create volumes on disks that are not boot drives. In fact, all > enterprises distros propose to set up even the boot drive with LVM > instead of partitionning and have been doing so for 10 years. > So I'm pretty sure having in ceph the option to use LVM instead of > partitionning would be a darn good thing :) > Thanks for the information :) Currently not really a option with Ceph. > Second: are you absolutely sure you can't partition a bcache device? > Does parted refuse to open and partition it? In which case, you may > only be missing some appropriate udev rules. > Yes, I'm sure. You can create the partitions, but they will not show up as devices which you can use due to a limitation in the bcache kernel driver. Patches [0] are out there to make this work, but they are not in bcache yet. Hence my thread if this support can be added. Wido [0]: https://yaple.net/2016/03/31/bcache-partitions-and-dkms/ > -- > ------------------------------------------------------------------------ > Emmanuel Florac | Direction technique > | Intellique > | <eflorac@xxxxxxxxxxxxxx> > | +33 1 78 94 84 02 > ------------------------------------------------------------------------ -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
