yeah, disk with badblock = disk with dynamic layout i think with badblock we could port layout to all raid systems (including raid1 hehe, i like raid1) the area for badblock, we could clena then at startup with: write 000000, send TRIM command to sectors used by badblock area, this will help disks with internal realloc functions (faster than md software) 2011/2/18 Keld Jørn Simonsen <keld@xxxxxxxxxx>: > On Fri, Feb 18, 2011 at 05:00:27PM -0200, Roberto Spadim wrote: >> again... for realloc we need TRIM command or reserved sectors just for >> bad block realloc, TRIM command tell MD what sector isn?t in use, at >> WRITE command MD set the sector as inuse, at array creation md set >> sector as inuse too. this will only work with ext4 and swap, others >> filesystem don?t have TRIM. the solution of others filesystem are >> based on not used block, but it?s a internal logic of each filesystem. >> i don?t know what is best, TRIM command is nice (we can send TRIM to >> disks, this help to make their life bigger) a bad block is a disk >> getting smaller and smaller, the disk can realloc badblock. if it >> cant, filesystem should realloc it (it have more information about >> logic device, it shouldn?t, TRIM command is the information that disk >> should have to discart blocks, not a filesystem logic, but... it?s a >> option, filesystem can realloc) > > I think I prefer a realloc area in the raid metadata area. And the > metadata area could be contaning a not-too-small realloc area, with an > option of enlarging the realloc area at a later time. This could be done > by shrinking the related file system, and then adding the freed space to > the realloc area in the raid metadata. > > Some MBs set aside for this would not be noticeable in todays TB disks > regime. I think current disk hardware allows relocation of under 1000 > blocks a 512 byte = under 512 kB. So no problem sizewise. > Performance may be a bigger problem. Maybe some binary searcheable list > built at MD RAID assembly time. > > best regards > keld > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Roberto Spadim Spadim Technology / SPAEmpresarial -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
