On Mon, 2004-10-11 at 20:13, Neil Brown wrote: > On Monday October 11, mingz@xxxxxxxxxxx wrote: > > :) thanks a lot. so now i know what policy raid1 use. so raid1 will > > randomly choose first drive and sync among all drives. so here comes to > > another question. after a power loss and reboot, raid1 knows that there > > are something wrong and potentially out of sync between two drives. will > > it try to check and make sure two drives are in sync or it just leave > > two drives there with potential unmatched blocks. > > > > for example, before reboot, a write to location A happen in progress. > > then after reboot. raid1 has no idea on previous write information. it > > just knows something might happened and two drives are possible to be > > out of sync. will it check whole drive to do a resync? > > > > Yes. It copies all of these first drive onto all of the other drives. a full copy? then if u have 100GB on first disk and you have to copy that much? with background reconstruction, this can take a long time. i never realized the overhead is this high. so i guess if system provide u a piece of nvram, u can do much better. :P > > NeilBrown -- -------------------------------------------------- | Ming Zhang, PhD. Student | Dept. of Electrical & Computer Engineering | College of Engineering | University of Rhode Island | Kingston RI. 02881 | e-mail: mingz at ele.uri.edu | Tel. (401) 874-2293 | Fax. (401) 782-6422 | http://www.ele.uri.edu/~mingz/ | http://crab.ele.uri.edu/gallery/albums.php -------------------------------------------------- - 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
