On Sun, 06 May 2012 11:46:21 +0000, Ramon Hofer wrote: > On Sat, 05 May 2012 11:15:22 +0000, Camaleón wrote:
>>> On the other hand it isn't possible to have different disk sizes in a >>> raid 6 neither. >> >> I think yes, that you can, but only the lowest of the disk capacities >> will be used (this applies to all of the RAID levels). Software RAID >> has not such limitaion because you can mirror partitions, instead. > > Ok so with sw raid I can use partitions as devices. This means I could > divide my drives into 500 GB pieces and like this use the whole size of > the disks? If your hard disk capacity is ~1.5 TiB then you can get 3 partitions from there of ~500 GiB of size (e.g., sda1, sda2 and sda3). For a second disk, the same (e.g., sdb1, sdb2 and sdb3) and so on... or you can make smaller partitions. I would just care about the whole RAID volume size. > Wouldn't it be easier to have e.g. four of each size and put them into > raid5? With software raid you have more choices because you can partition as you like: you can use the whole disk capacity or make small chunks and use them to be part of a RAID volume. Again, RAID5 is not something advisable and mdadm also supports RAID 6 :-) >>> So my plan seems still reasonable to me to have several 4 disks raid 5 >>> arrays. Like that I'm flexible to add bigger disks in future as they >>> become cheaper and still can keep my old 1.5 TB disks. And if I would >>> go for raid 6 with the 4 disk array I would loose a third of the >>> capacity. >> >> (...) >> >> You've been warned :-) > > Yes and I appreciate that! > But I can't see any other solution without loosing 500 GB of the two TB > disks :-? When using the whole hard disk capacity for the array: - A RAID 5 volume with x4 1.5 TiB disks will give you an available space of 4.5 TiB (the sum of the number of the disks minus 1 drive). - A RAID 6 volume with x4 1.5 TiB disks will give you an available space of 3 TiB (the sum of the number of the disks minus 2 drives). That's the price for the added data security. If you are constrained about hard disk space, remember that you can add LVM and your spacing problems are be solved >;-) Greetings, -- Camaleón -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/jo5q6o$kir$5...@dough.gmane.org