On Tue, Nov 15, 2011 at 06:47:36PM +0800, Yibin Shen wrote: > On Tue, Nov 15, 2011 at 6:38 PM, Christoph Hellwig <[email protected]> wrote: > > On Tue, Nov 15, 2011 at 06:34:32PM +0800, Yibin Shen wrote: > >> > How to store the checksum? Will this feature be implemented on Yuan's > >> > "farm"? > >> we will create a checksum file for each object, and named with object > >> name plus a suffix, > >> hmm, maybe this is conflicted with "farm" project, I will talked it with > >> Yuan. > > > > Can you investigate storing the checksum in an extended attribute? That > > would be a lot more efficient than creating another inode for it. > actually , use xattr to store checksum is what we thought firstly, > but xattr dependency of sheep has been removed not long ago, so we > choose to use file.
Is there a reason why xattrs need to be stricly avoided? In this case using them will provide huge benefits - instead of requiring at least one new inode and data blocks a reasonably small checksum will fit into the existing inode if using xattrs. So there will be two less (dependent) I/Os every time the object is read or updated. -- sheepdog mailing list [email protected] http://lists.wpkg.org/mailman/listinfo/sheepdog
