On Tue, Jun 03, 2008 at 09:37:27AM -0500, Thomas King wrote: > > All the issues he complains about actually are solved by XFS, and XFS > > actually > does better in > > exactly these environments than either zfs on Solaris or JFS2 on AIX. > > > > > > I asked the author that question and he states XFS is actually a pretty good > answer to most of those issues but believes it still falls short where "the > metadata areas are not aligned with RAID strips and allocation units are FAR > too > small but better than ext."
I think it would be best to let the XFS developers answer this part. But, XFS is designed for and used in massive installations, and I think it represents a scalability goal for Btrfs. > Another detail he brought out was sending data and > metadata to different devices in those environments and referenced RT XFS. > Otherwise having them on the same device increases the possibility of > corruption > and/or a longer filesystem check/repair. Will btrfs offer something like this > in > the future? Btrfs can duplicate metadata via the internal raid1 and raid10 code. On single spindles it will duplicate metadata as well. This is different from RT XFS which I do not understand well. There is not code today in btrfs to force data and metadata to different devices, but the disk format has the bits it needs to make that happen. I think it is an oversimplification to say that splitting the two between devices changes the chances of a corruption, or changes the time a repair takes. Btrfs does split data and metadata allocations, grouping metadata together in large chunks on the drive. This does make FS check/repair faster by reducing seeks between metadata blocks. > > Do y'all foresee btrfs being used in exabtye installations? Yes > Does/Will btrfs have RAID awareness in that it will align "the > superblock and metadata to the RAID stripe"? Today the superblock is not stripe aligned, but it will be in a future release that supports super block duplication. At least, the blocks that are frequently written will be striped aligned. > What is the largest block allocation available? 2^64 bytes. But, in COW filesystems massive extents have different costs than they do in traditional filesystems. It isn't always a good idea to make a huge extent. > Will btrfs be T10 DIF/block protect aware? I work closely with Martin, and we'll leverage the T10 DIF code as much as possible. > I remember reading that CRFS relies on btrfs, but will btrfs support NFS, > specifically version 4.1? > We'll definitely support NFS. It doesn't work today, but it will before 1.0. -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
