| 1 |
On Monday 25 August 2014 13:35:11 Kerin Millar wrote: |
| 2 |
> On 25/08/2014 12:17, Peter Humphrey wrote: |
| 3 |
> |
| 4 |
> <snip> |
| 5 |
> |
| 6 |
> > Well, it was simple. I just said "rc-update del mdraid boot" and all is |
| 7 |
> > now |
| 8 |
> > well. I'd better revisit the docs to see if they still give the same |
| 9 |
> > advice. |
| 10 |
> |
| 11 |
> Very interesting indeed. |
| 12 |
|
| 13 |
You wrote this e-mail after the other two, so I'll stick to this route, |
| 14 |
leaving the other idea for later if needed. |
| 15 |
|
| 16 |
> I now wonder if this is a race condition between the init script running |
| 17 |
> `mdadm -As` and the fact that the mdadm package installs udev rules that |
| 18 |
> allow for automatic incremental assembly? |
| 19 |
|
| 20 |
Isn't it just that, with the kernel auto-assembly of the root partition, and |
| 21 |
udev rules having assembled the rest, all the work's been done by the time the |
| 22 |
mdraid init script is called? I had wondered about the time that udev startup |
| 23 |
takes; assembling the raids would account for it. |
| 24 |
|
| 25 |
> Refer to /lib/udev/rules.d/64-md-raid.rules and you'll see that it calls |
| 26 |
> `mdadm --incremental` for newly added devices. |
| 27 |
|
| 28 |
# ls -l /lib/udev/rules.d | grep raid |
| 29 |
-rw-r--r-- 1 root root 2.1K Aug 23 10:34 63-md-raid-arrays.rules |
| 30 |
-rw-r--r-- 1 root root 1.4K Aug 23 10:34 64-md-raid-assembly.rules |
| 31 |
|
| 32 |
> With that in mind, here's something else for you to try. Doing this will |
| 33 |
> render these udev rules null and void: |
| 34 |
> |
| 35 |
> # touch /etc/udev/rules.d/64-md-raid.rules |
| 36 |
|
| 37 |
I did that, but I think I need instead to |
| 38 |
# touch /etc/udev/rules.d/63-md-raid-arrays.rules |
| 39 |
# touch /etc/udev/rules.d/64-md-raid-assembly.rules |
| 40 |
|
| 41 |
I'll try it now... |
| 42 |
|
| 43 |
> Thereafter, the mdraid script will be the only agent trying to assemble |
| 44 |
> the 1.x metadata arrays so make sure that it is re-enabled. |
| 45 |
|
| 46 |
Right. Here's the position: |
| 47 |
1. I've left /etc/init.d/mdraid out of all run levels. I have nothing but |
| 48 |
comments in mdadm.conf, but then it's not likely to be read anyway if the |
| 49 |
init script isn't running. |
| 50 |
2. I have empty /etc/udev rules files as above. |
| 51 |
3. I have kernel auto-assembly of raid enabled. |
| 52 |
4. I don't use an init ram disk. |
| 53 |
5. The root partition is on /dev/md5 (0.99 metadata) |
| 54 |
6. All other partitions except /boot are under /dev/vg7 which is built on |
| 55 |
top of /dev/md7 (1.x metadata). |
| 56 |
7. The system boots normally. |
| 57 |
|
| 58 |
> I'm not actually sure that there is any point in calling mdadm -As where |
| 59 |
> the udev rules are present. I would expect it to be one approach or the |
| 60 |
> other, but not both at the same time. |
| 61 |
|
| 62 |
That makes sense to me too. Do I even need sys-fs/mdadm installed? Maybe I'll |
| 63 |
try removing it. I have a little rescue system in the same box, so it'd be |
| 64 |
easy to put it back if necessary. |
| 65 |
|
| 66 |
> Incidentally, the udev rules were a source of controversy in the |
| 67 |
> following bug. Not everyone appreciates that they are installed by default. |
| 68 |
> |
| 69 |
> https://bugs.gentoo.org/show_bug.cgi?id=401707 |
| 70 |
|
| 71 |
I'll have a look at that - thanks. |
| 72 |
|
| 73 |
-- |
| 74 |
Regards |
| 75 |
Peter |
Archives