Hi Emmanuel, Zitat von Emmanuel Florac <eflorac@xxxxxxxxxxxxxx>:
[...] 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 :)
I disagree. As a matter of fact, it'd be a bad idea IMO: Unlike with what you have given as good examples for LVM usage, the disk layout on OSDs is fixed. So you're throwing in a (rather fast, but unnecessary) code path intended to provide flexibility, where you need none. This causes delays and provides potential problems that can be avoided. Another counter-example: You wouldn't put LVM on a disk that's intended as a (100%) MD-RAID volume, and add an LV as RAID member... you'll add a partition table for a reason, but no extra layer between the partition and the RAID stuff.
Second: are you absolutely sure you can't partition a bcache device?
While I haven't tried in a while, that's the way it was when I tested last. No partitioning of the bcache device. If you want multiple bcached partitions on a backing store, partition first and then create multiple bcached devices. This could be done with the BlueStore installer as well, but somebody will have to provide the code to optionally bcache the partitions.
Regards, J -- 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
