From mboxrd@z Thu Jan 1 00:00:00 1970 From: Roman Kapusta Subject: Re: Why does Btrfs allow raid1 with mismatched drives? Also: How to look behind the curtain Date: Thu, 5 Jan 2012 14:35:00 +0100 Message-ID: References: <4D48BA4B-AB66-46A2-8E79-050B798C9A3E@gmail.com> <20120105094444.GF27122@carfax.org.uk> <201201051139.20334.Martin@lichtvoll.de> <82FEA956-FFE4-4A00-B895-AA381A35FEE7@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Martin Steigerwald , linux-btrfs@vger.kernel.org, Hugo Mills To: Fabian Zeindl Return-path: In-Reply-To: <82FEA956-FFE4-4A00-B895-AA381A35FEE7@gmail.com> List-ID: On Thu, Jan 5, 2012 at 13:26, Fabian Zeindl w= rote: > > On Jan 5, 2012, at 11:39 , Martin Steigerwald wrote: >> "Allocating as many chunks as can fit across the drives" is also pre= tty >> clear to me. So if BTRFS can=C2=B4t allocate a new chunk on two devi= ces, its >> full. To me it seems obvious that BTRFS will not break the RAID-1 >> redundancy guarentee unless a drive fails. > > So (assuming 1GB chunksize): > > if i create a raid-1, btrfs with a 3GB and a 7GB device, it will show= me ~10GB free space, > after saving a 1GB file, i will have 8GB left (-1GB on each device) > after saving another 1GB, i will have 6GB left (--- " ----) > after saving another 1GB, it's "suddenly" full? you have still 4GB free of non RAID-1 (single) space, which is currently unavailable, but it is planned that BTRFS will support mixed storage: some files can be RAID-1, some files can be RAID-0 and rest is basic (single) storage > > Fabian-- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs= " in > the body of a message to majordomo@vger.kernel.org > More majordomo info at =C2=A0http://vger.kernel.org/majordomo-info.ht= ml -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html