Change small filesystem to normal
Hi, I've created a small BTRFS filesystem, where metadata+data are mixed (and metadata are not DUP'ed). Then I've enlarged the FS to 1 GB ; now I'd like to make it normal with separate data and metadata, and DUP'ed metadata. Is there a way tp do this without reformatting the FS ? TIA, kind regards. -- Swâmi Petaramesh sw...@petaramesh.org http://petaramesh.org PGP 9076E32E Ne cherchez pas : Je ne suis pas sur Facebook. -- 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: Change small filesystem to normal
On Sun, Jul 22, 2012 at 05:06:24PM +0200, Swâmi Petaramesh wrote: Hi, I've created a small BTRFS filesystem, where metadata+data are mixed (and metadata are not DUP'ed). Then I've enlarged the FS to 1 GB ; now I'd like to make it normal with separate data and metadata, and DUP'ed metadata. Is there a way tp do this without reformatting the FS ? No, currently there is no way to do this. You'll have to create a new filesystem with mkfs.btrfs. Thanks, Ilya -- 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: Change small filesystem to normal
On Sun, 22 Jul 2012 17:06:24 +0200 Swâmi Petaramesh sw...@petaramesh.org wrote: Hi, I've created a small BTRFS filesystem, where metadata+data are mixed (and metadata are not DUP'ed). Then I've enlarged the FS to 1 GB ; now I'd like to make it normal with separate data and metadata, and DUP'ed metadata. Considering the metadata overallocation bug [1] is still not fixed even in the latest kernels and no one seems to care all that much, I would not recommend doing that. Personally I now use a mixed filesystem on a 1TB disk without any problems, and do not think there's anything wrong with mixed. In fact there's been some talk of moving to the mixed mode allocation to be used by default, and maybe even removing support for the split mode: see [2]. [1] http://comments.gmane.org/gmane.comp.file-systems.btrfs/17848 [2] http://kerneltrap.org/mailarchive/linux-btrfs/2010/10/29/6885925 -- With respect, Roman ~~~ Stallman had a printer, with code he could not see. So he began to tinker, and set the software free. signature.asc Description: PGP signature
Re: Change small filesystem to normal
You're painfully right Roman, A freshly formatted 1 GB BTRFS filesystem on which 81 MB of data has been put shows only ~260 MB of free space and reserves something like 2 x 380 MB of metadata. This is absolutely ridiculous of BTRFS... :-/ Kind regards. Le 22/07/2012 17:37, Roman Mamedov a écrit : On Sun, 22 Jul 2012 17:06:24 +0200 Swâmi Petaramesh sw...@petaramesh.org wrote: Hi, I've created a small BTRFS filesystem, where metadata+data are mixed (and metadata are not DUP'ed). Then I've enlarged the FS to 1 GB ; now I'd like to make it normal with separate data and metadata, and DUP'ed metadata. Considering the metadata overallocation bug [1] is still not fixed even in the latest kernels and no one seems to care all that much, I would not recommend doing that. Personally I now use a mixed filesystem on a 1TB disk without any problems, and do not think there's anything wrong with mixed. In fact there's been some talk of moving to the mixed mode allocation to be used by default, and maybe even removing support for the split mode: see [2]. [1] http://comments.gmane.org/gmane.comp.file-systems.btrfs/17848 [2] http://kerneltrap.org/mailarchive/linux-btrfs/2010/10/29/6885925 -- 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: Change small filesystem to normal
On Sun, Jul 22, 2012 at 10:55 PM, Swâmi Petaramesh sw...@petaramesh.org wrote: You're painfully right Roman, A freshly formatted 1 GB BTRFS filesystem on which 81 MB of data has been put shows only ~260 MB of free space and reserves something like 2 x 380 MB of metadata. This is absolutely ridiculous of BTRFS... :-/ That's an artifact of the small size of that filesystem and the default size of allocations, which is why mixed mode exists. The metadata allocation is about 4% on most filesystems: I see 38gb of allocated but unused metadata space on a 900gb fs and 70gb on a 1.7tb fs, and the referenced threads reports 170gb on what appears to be a 4tb fs; while not ideal, it's not remotely as bad as the 25% overhead of the minimum 256mb*2 metadata allocation on a small 1gb fs*. The behaviour of a small filesystem simply isn't the same as the behaviour of a large filesystem. * Note that 1gb is still considered a very rather btrfs filesystem, for which mixed mode is recommended! -- 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: Change small filesystem to normal
* Note that 1gb is still considered a very rather btrfs filesystem, for which mixed mode is recommended! Deleted the wrong word: a rather small btrfs filesystem is what I intended. -- 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
