Re: UI issues around RAID1
- Unless I'm missing something, there doesn't seem to be any way later on to see that I set the data policy to raid1, except using btrfs-dump-tree and checking the flags bits for the appropriate group. Which can make things confusing if I have a bunch of btrfs filesystems around. You aren't missing anything, theres just nothing that spits that information out yet. btrfs-show would probably be a good place to do this. Thanks. I'll look at adding in show more info about RAID policy to the btrfs-show output. - R. -- To unsubscribe from this list: send the line unsubscribe linux-btrfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: UI issues around RAID1
Yeah df is just a fun ball of wax in many respects. We don't take into account RAID and we don't subtrace space thats strictly for metadata, so there are several things that need to be fixed for df. Thanks, But as we have said many times... if we have different raid types active on different files, any attempt to make df report raid adjusted numbers instead of the current raw total storage numbers is going to sometimes give wrong answers. So I think it is dangerous to try. The current output may be ugly, but it is always consistent and explainable. It does seem like a big problem, especially as we add in other RAID levels etc. However on the flip side, the accounting of the used space does seem off and maybe fixable? In other words if I create a btrfs filesystem out of two 1GB devices with RAID1 for data and metadata, then df shows a total size of 2GB for the filesystem. But if I then create a .5 GB file on that filesystem, the used space is shown as .5 GB only -- ie the accounting of total size is at the device/block level, but the accounting of used space is at the logical/filesystem level. Which leads to very confusing df output. I wonder if it's possible to come up with a way to make things consistent at least, or figure out a way to define more useful information about space left on the filesystem. - Roland -- To unsubscribe from this list: send the line unsubscribe linux-btrfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
UI issues around RAID1
I've just started playing around with btrfs RAID1, and I've noticed a couple of what seem to be UI issues. Suppose I do something like mkfs.btrfs -d raid1 -m raid1 dev1 dev2. I see the following minor usability problems: - Unless I'm missing something, there doesn't seem to be any way later on to see that I set the data policy to raid1, except using btrfs-dump-tree and checking the flags bits for the appropriate group. Which can make things confusing if I have a bunch of btrfs filesystems around. - The free space reporting doesn't seem to take into account the fact that everything is going to be mirrored; so df et al report the size of the filesystem and free space on the new filesystem as size(dev1) + size(dev2) -- if dev1 and dev2 are the same size then I would assume it should really be just size(dev1) for a fully-RAID1 filesystem. (Not sure in general what we should say for a metadata-only mirrored filesystem, since we don't really know in advance how much space we have exactly) I'm happy to help fix these issues up; just want to make sure I'm not missing something or doing it wrong. Thanks, Roland -- To unsubscribe from this list: send the line unsubscribe linux-btrfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Btrfs for mainline
I don't disagree, please do keep in mind that I'm not suggesting anyone use this in production yet. When it's in mainline I suspect people will start using it for that. I think the larger question here is where we want development to happen. I'm definitely not pretending that btrfs is perfect, but I strongly believe that it will be a better filesystem if the development moves to mainline where it will attract more eyeballs and more testers. One possibility would be to mimic ext4 and register the fs as btrfsdev until it's considered stable enough for production. I agree with the consensus that we want to use the upstream kernel as a nexus for coordinating btrfs development, so I don't think it's worth waiting a release or two to merge something. - R. -- To unsubscribe from this list: send the line unsubscribe linux-btrfs in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
