> > Hi all, > > > > I understand, that a change from RAID5 to RAID6 by adding a single disk - > > eg. keeping the number of data disks - requires a backup file throughout the > > whole reshape process. For a larger, multi-TB array this means millions of > > writes to the backup file, which - if i'm correct - means means millions of > > writes to the same physical sectors of the disk that holds the backup file. > > Is this not problematic? How many write operations can a typical drive > > tolerate nowadays? (on the same sectors) > Lots, where Lots >= 1 and Lots < infinity. > I've never seen rotating media specify any form of limitation to writes. > Have you? No, that's why i'm asking. Imho, in typical usage, write cycle counts on a certain sector may not be that high, even on a database server. I doubt it ever goes over a few hundred thousands during the life cycle of the hard disk. On the other hand, a single reshape on a larger array can trigger tens of millions of write cycles on certain sectors. Sectors do fail eventually, so I'm wondering if the "no limit" is truly a no limit, or manufacturers just won't state this info because in "normal" usage, customers will never reach that limit. Btw, i'm sure SSD's are not meant to take such a pressure. Cheers, Peter -- 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
