I have Ubuntu Server 11.04 running in Virtualbox on my Mac (this is so I can test setting up the server a thousand times before actually building a physical one).
In virtualbox, I have given the server:
8GB drive for the OS
3x4GB drives for a RAID 5 array.
after having run mdadm, I check it by looking at /proc/mdstat.
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid 5] [raid4] [raid10]
md0 : active raid5 sdd1 sdc1 sdb1
8383488 blocks super 1.2 level 5, 512k chunk, algorithm 2 [3/3] [UUU]
(Hopefully there are no typos above, I had to type it in by hand because copying is not currently working)
My concern is that sdd1 is marked as . I have almost no understanding of mdadm (but I am actively trying to learn). This website http://unthought.net/Software-RAID.H...D.HOWTO-6.html
would suggest that - if I am not using a spare - the highest number any drive should be exhibiting would be n-1 (where n is the number of drives in the array). In my case, that should be , no? But here is is showing .
mdadm --detail /dev/md0
gets me the following output:
Version : 1.2
Creation Time : Sun Sep 25 13:33:42 2011
Raid Level : raid5
Array Size : 8383488 (8.00 GiB 8.58 GB)
Used Dev Size : 4191744 (4.00 GiB 4.29 GB)
Raid Devices : 3
Total Devices : 3
Persistence : Superblock is persistent
Update Time : Sun Sep 25 13:47:16 2011
State : clean
Active Devices : 3
Working Devices : 3
Failed Devices : 0
Spare Devices : 0
Layout : left-symmetric
Chunk Size : 512K
Name : ubuntu:0 (local to host ubuntu)
UUID : 8b7364ba:f9534103:4fd09587:d5c2659e
Events : 18
Looking at this output I am mildly reassured because it shows 3 active devices and 0 spare devices. Can someone explain what I am supposed to glean from /proc/mdstat?