On Tue, 2004-04-27 at 05:09, thornber@redhat.com wrote: > On Tue, Apr 27, 2004 at 11:57:58AM +0200, christophe.varoqui@free.fr wrote: > > Selon thornber@redhat.com: > > > > > On Sun, Apr 25, 2004 at 11:54:59PM +0200, christophe varoqui wrote: > > > > * add the dmadm WIP tool (read MD superblocks and create > > > > corresponding devmaps when possible) > > > > > > :) > > > > > Any insight on where to put the log of the mirror target when mapping over a > > MD-created raid1 ? > > MD effectively uses a log with a single region in it. So we only need > 3 sectors (2 for the header 1 for the bitset) for the log, is there > any space in the MD metadata where this could be placed ? > > - Joe The MD device size is 64K aligned and MD superblock size is 4K. In term of sectors, the calculation is as follows: MD_SB_BYTES 4096 MD_SB_SECTORS (MD_SB_BYTES / 512) // x is the child device size in sectors. #define MD_RESERVED_BYTES (64 * 1024) #define MD_RESERVED_SECTORS (MD_RESERVED_BYTES / 512) #define MD_NEW_SIZE_SECTORS(x) (((x) & ~(MD_RESERVED_SECTORS -1)) - MD_RESERVED_SECTORS) It's safe to write the log after the MD superblock. Regards, Mike T. - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
