Aaron Toponce put forth on 7/12/2010 5:16 PM: > On 7/12/2010 4:13 PM, Stan Hoeppner wrote: >> Is that a typo, or are you turning those 3 disk mdadm sets into RAID10 as >> shown above, instead of the 3-way mirror sets you stated previously? RAID 10 >> requires a minimum of 4 disks, you have 3. Something isn't right here... > > Incorrect. The Linux RAID implementation can do level 10 across 3 disks. > In fact, it can even do it across 2 disks.
Only throw the bold "incorrect" or "correct" statements around when you really know the subject material. You don't. Linux md RAID 10 is not standard RAID 10 when used on 2 and 3 drives. When used on 3 drives it's actually RAID 1E, and on two drives it's the same as RAID1. Another Wikipedia article linked within the one you quoted demonstrates this. Note the page title "Non-standard_RAID_levels". http://en.wikipedia.org/wiki/Non-standard_RAID_levels Linux MD RAID 10 The Linux kernel software RAID driver (called md, for "multiple device") can be used to build a classic RAID 1+0 array, but also (since version 2.6.9) as a single level[4] with some interesting extensions[5]. The standard "near" layout, where each chunk is repeated n times in a k-way stripe array, is equivalent to the standard RAID-10 arrangement, but it does not require that n divide k. For example an n2 layout on 2, 3 and 4 drives would look like: 2 drives 3 drives 4 drives -------- ---------- -------------- A1 A1 A1 A1 A2 A1 A1 A2 A2 A2 A2 A2 A3 A3 A3 A3 A4 A4 A3 A3 A4 A4 A5 A5 A5 A6 A6 A4 A4 A5 A6 A6 A7 A7 A8 A8 .. .. .. .. .. .. .. .. .. *The 4-drive example is identical to a standard RAID-1+0 array, while the 3-drive example is a software implementation of RAID-1E. The 2-drive example is equivalent RAID 1.* -- Stan -- 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/4c3baabe.2080...@hardwarefreak.com
