This is from "man mdadm": As well as reporting events, mdadm may move a spare drive from one array to another if they are in the same spare-group and if the desti- nation array has a failed drive but not spares. You can do what you want. I have never tried. My arrays are too different. I don't want to waste an 18Gig spare on a 256M array. Guy -----Original Message----- From: linux-raid-owner@xxxxxxxxxxxxxxx [mailto:linux-raid-owner@xxxxxxxxxxxxxxx] On Behalf Of maarten Sent: Thursday, January 06, 2005 9:17 AM To: linux-raid@xxxxxxxxxxxxxxx Subject: Spares and partitioning huge disks Hi I just got my 4 new 250GB disks. I have read someone on this list advocating that it is better to build arrays with smaller volumes, as that decreases the chance of failure, especially failures of two disks in a raid5 configuration. The idea behind it was that since a drive gets kicked when a read-error occurs, the chance is lower that a 40 GB part develops a read error than for the full size 250 GB. Thus, if you have 24 40GB parts, there is no fatal two disk failure when part sda6 and part sdc4 develop a bad sector at the same time. On the other hand, if the (full-size) disk sda1 and sdc1 do fail at the same time, you're in deep shit. I thought it was real insightful, so I would like to try that now. (Thanks to the original poster, I don't recall your name, sorry) Now my two questions regarding this. 1) What is better, make 6 raid5 arrays consisting of all 40GB partitions and group them in a LVM set, or group them in a raid-0 set (if the latter is even possible that is) ? 2) Seen as the 'physical' volumes are now 40 GB, I could add an older 80GB disk partitioned in two 40GB halves, and use those two as hot-spares. However, for that to work you'd have to be able to add the spares to _all_ raid sets, not specific ones, if you understand what I mean. So they would act as 'roaming' spares, and they would get used by the first array that needs a spare (when a failure occurs of course). But... is this possible ? Thanks for any insights! Maarten -- - 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 - 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
