Penguin
Annotated edit history of RaidNotes version 7 showing authors affecting page license. View with all changes included.
Rev Author # Line
6 JohnMcPherson 1 !! mdadm: _device_ is too small: 0K
2 <verbatim>
3 mdadm: /dev/sda3 is too small: 0K
4 mdadm: create aborted
5 </verbatim>
1 KragenSitaker 6
6 JohnMcPherson 7 Check that the /dev/sda3 special file is actually correct. If you inadvertantly screw up your mdadm command (eg giving /dev/sda3 as the first non-option argument), then mdadm will quite happily replace your /dev/sda3 special with an md special:
1 KragenSitaker 8
6 JohnMcPherson 9 <verbatim>
10 # ls -ld /dev/sda*
11 brw-rw---- 1 root disk 8, 0 2009-05-05 18:20 /dev/sda
12 brw-rw---- 1 root disk 8, 1 2009-05-05 19:14 /dev/sda1
13 brw-rw---- 1 root disk 8, 2 2009-05-05 19:19 /dev/sda2
14 brw-r--r-- 1 root root 9, 0 2009-05-05 20:06 /dev/sda3
15 </verbatim>
16 To fix (obviously replacing "sda3" with whatever device you are actually having problems with):
17 <verbatim>
18 # rm /dev/sda3
19 # mknod /dev/sda3 b 8 3
20 </verbatim>
1 KragenSitaker 21
6 JohnMcPherson 22 !!Migrating an existing partition to raid1
23 You can create a raid1 that is initially degraded; once all the data is on it and you are running from that, then you can add more devices to the raid1 and it will "rebuild" it in the background.
3 KragenSitaker 24
6 JohnMcPherson 25 Eg:
26 <verbatim>
27 # mdadm --create /dev/md0 --raid-devices=2 --level=raid1 /dev/sdb1 missing
5 CraigBox 28
6 JohnMcPherson 29 size=296696452K mtime=Tue May 5 19:29:00 2009
30 mdadm: array /dev/md0 started.
31 # (mkfs.xxx /dev/md0)
32 # (mount and cp stuff from sda1 to /dev/md0)
33 # ... (once sda1 is no longer in use, and the same size)
34 # mdadm --add /dev/md0 /dev/sda1
35 </verbatim>
7 AlPyat 36 ----
37 !!Resources:
38 * [RAID Center-RAID Disk Space Calculator, Tools and Comparison Charts|http://www.icc-usa.com/store/pc/viewContent.asp?idpage=7]
5 CraigBox 39 ----
40 CategoryDiskNotes