Am 10.07.19 um 04:18 schrieb Adam Goryachev: > On 10/7/19 11:57 am, Reindl Harald wrote: >> Am 10.07.19 um 03:28 schrieb Adam Goryachev: >>> PS, unless you were referring to 3 disk RAID10 as a joke? >> exactly >> >>> TBH, I really don't understand RAID10, other than improving performance. >>> For example, in a 10 drive RAID10, you have a higher probability to lose >>> 2 drives that are a "pair" than losing 3 drives in total from a 7 drive >>> RAID6 (both events lead to total data loss, although potentially you >>> could recover more "usable" data from the RAID10 array since you would >>> more likely have a large amount of contiguous data). >> RAID10 is about performance *and* redundancy *as well* as storage size >> >> as said: 3 disk RAID10 is a joke and a 3 disk RAID1 is waste of size >> >> 3x2 TB RAID1 = 2 TB useable >> 4x2 TB RAID10 = 4 TB useable > > So for the cost of an extra 2TB drive, you got: > > 1) An extra 2TB capacity - which the OP doesn't need > 2) Less data protection, you can only lose a MAXIMUM of 2 disks without > losing data, but if you lose the "wrong" 2 disks, then you lost all your > data. > > Using 4 x 2TB RAID1 (ie, same cost/number of disks) would mean you can > lose any 3 disks with no data loss, and when you replace them, quick and > simple recovery process. Even 3 x 2TB allows for ANY 2 disk failure > without data loss. > > The OP stated that performance and capacity was not something that > interests him. The primary concern was avoiding the loss of data, > presumably due to drive failure, perhaps availability is also important. > 2TB is sufficient for 5 years. don't change the fact that a 2 TB HDD (when we say performance is not important) costs nothing these days and with RAID1 you are limited to the write speed of a single disk so if you are paranoid about drive failures get 6x1 TB = 300 € with 3 TB useable which is exatcly between 3x2 RAID1 and 4x2 RAID10 :-) that's 60 € per year over 5 years or one beer less per week....
