> 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 > > Chris,
Thanks a ton for answering all these questions. I've asked the XFS developers what was discussed here and they gave some excellent info as well. Enjoy your day! Tom King -- 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
