> -----Original Message----- > From: linux-btrfs-owner@xxxxxxxxxxxxxxx [mailto:linux-btrfs- > owner@xxxxxxxxxxxxxxx] On Behalf Of sam tygier > Sent: Wednesday, 6 May 2015 7:18 AM > To: linux-btrfs@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] btrfs-progs: check metadata redundancy > > On 05/05/15 15:54, David Sterba wrote: > > On Sat, May 02, 2015 at 05:03:31PM +0100, sam tygier wrote: > >> Currently BTRFS allows you to make bad choices of data and metadata > >> levels. For example -d raid1 -m raid0 means you can only use half > >> your total disk space, but will loose everything if 1 disk fails. > >> This patch prevents you creating the situation another will be need > >> to prevent rebalancing in to it. > >> > >> When making a filesystem check that metadata mode is at least as > >> redundant as the data mode. For example don't allow: > >> -d raid1 -m raid0 > > > > This is enforcing some policty that makes sense for some usecases, but > > I think that the tool should be flexible enough to create any kind of > > raid profiles. It's up to the user. I'm willing to add a warning that > > the profiles seem fishy, but failing mkfs without any way to override > > that is IMHO not a good thing. > > There already seems to be policy in test_num_disk_vs_raid() disallowing > DUP for multiple devices. Is there really a useful case better protected data > than metadata? I would appreciate being able to use the DUP profile for data on a single disk - at the moment I just resort to partitioning the disk in two and creating a raid1. Usecase is portable disk backups - I take a master backup at site A with slow internet, and upload it to backup server from site B. Then I use rsync and snapshots. I start over every 2 months as one of the backups is an incremental backup of a few windows system images. Paul. -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
