would be really cool if a TRIM to the loopback device would do a 'hole punch' on the file Remco On Feb 26, 2013, at 7:25 AM, Suman C <schakrava@xxxxxxxxx> wrote: > Thanks for the sparse file idea, I am actually using that solution > already. I am not sure if its the best way, however. > > Suman > > On Mon, Feb 25, 2013 at 9:57 PM, Roman Mamedov <rm@xxxxxxxxxx> wrote: >> On Mon, 25 Feb 2013 21:35:08 -0800 >> Suman C <schakrava@xxxxxxxxx> wrote: >> >>> Yes, zvol like feature where a btrfs subvolume like construct can be >>> made available as a LUN/block device. This device can then be used by >>> any application that wants a raw block device. iscsi is another >>> obvious usecase. Having thin provisioning support would make it pretty >>> awesome. >> >> I think what you are missing is that btrfs is a filesystem, not a block device >> management mechanism. >> >> For your use case can simply create a snapshot and then make a sparse file >> inside of it. >> >> btrfs sub create foobar >> dd if=/dev/zero of=foobar/100GB.img bs=1 count=1 seek=100G >> >> If you need this to be a block device, use 'losetup' to make foobar/100GB.img >> appear as one (/dev/loopX). But iSCSI/AoE/NBD can export files as well as block >> devices, so this is not even necessary. >> >> -- >> With respect, >> Roman > -- > 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 -- 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
