Gentoo Archives: gentoo-user

From: Einux <einuxnet@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] How to change from one harddrive to software raid
Date: Thu, 31 Mar 2011 01:23:43
Message-Id: AANLkTiksBuMY5GtfVq3CB9LZtDYk7oeDsLCbHw=kYXM=@mail.gmail.com
In Reply to: Re: [gentoo-user] How to change from one harddrive to software raid by Joost Roeleveld
1 thank you guys, you've been helpful :)
2
3 On Wed, Mar 30, 2011 at 3:31 PM, Joost Roeleveld <joost@××××××××.org> wrote:
4
5 > On Wednesday 30 March 2011 07:28:40 Florian Philipp wrote:
6 > > Am 30.03.2011 05:02, schrieb Einux:
7 > > > Hi,
8 > > >
9 > > > I bought a new 1T harddrive which is exactly the same as my previous
10 > > > harddrive. So I'm planning to make a Raid-1 layout(for security
11 > > > reasons). But here's the problem: I've already setup LVM2 on the
12 > > > existing harddrive and I don't want to destroy the existing LVM volume
13 > > > groups. I tried to google it, but I'm not sure which is the right
14 > > > keyword. Could you guys help me out?
15 > > >
16 > > > Thanks in advance:)
17 > >
18 > > 1. Create a degenerated RAID1 with your new disk
19 > > mdadm --create /dev/md0 --level=1 --raid-devices=2 missing /dev/sdb
20 > >
21 > > 2. Partition the raid device
22 > >
23 > > 3. Add one of the partitions to your LVM volume group.
24 > > pvcreate /dev/sdb2
25 > > vgextend volume_group /dev/sdb2
26 > >
27 > > 4. Move everything from the old physical volumes to the new pv.
28 > > pvmove /dev/sda3 /dev/sdb2
29 > >
30 > > 5. Remove the old and now empty physical volume
31 > > vgreduce volume_group /dev/sda3
32 > >
33 > > 6. Move everything else which is not on LVM to your new raid. Guess you
34 > > need to go to single user mode to do this safely.
35 > >
36 > > 7. Grow your raid to also contain the old disk.
37 > > mdadm /dev/md0 -a /dev/sda
38 > >
39 > > No, I have not tested this and you should double-check everything. No
40 > > guarantees, etc.
41 > >
42 > > One warning, though: pvmove is known to create problems from time to
43 > > time. Leaking memory, bogging systems with infinite system load and so
44 > > on. If it gives you trouble, you can abort it with `pvmove --abort` and
45 > > try it again later by calling `pvmove volume_group` (without physical
46 > > device specified) to resume it. It SHOULD survive system crashes.
47 > > Trying another kernel version sometimes helps when pvmove gives you
48 > trouble.
49 >
50 > To avoid that, with "large" moves, do the following:
51 > # pvmove -i 600 /dev/sda3
52 >
53 > The "-i 600" means, only report every 10 minutes. It's the "reporting" that
54 > causes the memory leak.
55 >
56 > Also, when just wanting to "empty" one physical volume, it is not necessary
57 > to
58 > specify the "target".
59 > It's a good idea to mark the PVs on the existing drive "non-allocatable".
60 > Then
61 > LVM won't try to move anything to that PV:
62 > # pvchange -xn /dev/sda3
63 >
64 > The rest of the steps read correct. It's how I did a similar operation, but
65 > still double-check all the parameters and when in doubt, read the manual
66 > and/or ask on the list.
67 >
68 > --
69 > Joost Roeleveld
70 >
71 >
72 >
73
74
75 --
76 Best Regards,
77 Einux

Replies

Subject Author
Re: [gentoo-user] How to change from one harddrive to software raid Mark Shields <laebshade@×××××.com>