On Mon, 15 Jul 2013 22:34:15 +0200 Rave it chat-to-me@raveit.de wrote:
Hmm, for me me this is more a question how can i configure bcache or dm-cache in a system which use more than one SSD and some conventional hard-disk. Seems like only you or some kernel devs know about how to do this. Can you give a configuration example for f19? For example, i use 4 SSD at a hardware-raid for my several systems (f17/f18/f19/rawhide), i called it A, i need this for testing compiz on baremetal for all current fedora releases. On a second hardware-raid- controller i have 4 conventional disks to store my data, i called it B. So, if i add another SSD for bcache or dm-cache, i called C, how can i configure it? 1. this configuration should not control disk A 2. disk C should use as cache for disk B
Is this possible to configure? Do you have a link with more info's and configuration examples.
best regards, Wolfgang
First off -- bcache requires an additional superblock on the backing disk / block device -- in this case, B. So you would have to reformat the entire B array if you wanted to use bcache on it.
With that in mind, see: http://evilpiepirate.org/git/linux-bcache.git/tree/Documentation/bcache.txt?...
""" make-bcache -B /dev/path/to/B -C /dev/new/SSD
...
The devices show up as:
/dev/bcache<N>
As well as (with udev):
/dev/bcache/by-uuid/<uuid> /dev/bcache/by-label/<label>
To get started:
mkfs.ext4 /dev/bcache0 mount /dev/bcache0 /mnt """
That document should help answer some of your questions about bcache.
Best regards, Conrad