On Jun 8, 2013, at 10:31 PM, Stan Hoeppner <stan@xxxxxxxxxxxxxxxxx> wrote: > On 6/8/2013 1:18 PM, Ramon Hofer wrote: >> Dear Stan and linux-raid list > > Hi Ramon. > >> My home server with a linear raid (md0) containing three raid5 (md1, >> md2, md3) is still working wonderfully. Thanks again Stan! > > Glad to hear it. :) > > <snip> >> Is this possible and a good idea? > > No, it is not possible to expand a linear array this way. > ... >> If in some years one of the oldest 1.5 TB disks of md2 or any other >> fails, I could replace it with a bigger one and at the same time the >> other disks of the same device as well and get additional space? > > You can use the extra capacity, but not in the way you're considering. > This is due to the characteristics of a linear array. > > You have been using raw disks, not partitions. So when you replace a > dead drive you will need to create a partition on the replacement that > is the same size or a few sectors larger than the disk being replaced. > You will then use this partition as the replacement device in the array > rebuild. After you have replaced all 4 drives in this manner, you will > create a 2nd partition in the free space on each. You will then create > another RAID5 array from these 4 partitions and add it just as you did > the other RAID5s. > A raid0 can be converted to a degraded raid4 - after that, is it not possible to expand it to use the remaining space then convert back to raid0? I think I tested this a while back and it worked, but you would probably want to test it yourself first... I still think you'd be better off converting things to raid6 though.... larger drives + raid6 and you could still increase capacity too... Sam -- 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
