On 03/09/2025 12:55, Stefanie Leisestreichler (Febas) wrote:
Hi.
I have the system layout shown below.
To avoid data loss, I want to change HDs which have about 46508 hours of
up time.
I thought, instead of degrading, formatting, rebuilding and so on, I could
- shutdown the computer
Why degrade? There's no need.
But yes, unless you have hot-swap, you will need to shut down the
computer at some point ... and I'd recommend at least one reboot...
First things first - do you have a spare SATA port on your mobo? Or (I
wouldn't particularly recommend it) an external USB thingy to drop
drives in? The latter will let you hot swap and avoid one reboot.
Okay. Plug your new drive in however. You will know which drives are
your raid, so you just partition the third identically to the other two.
I'm surprised if your drives are MBR not GPT - MBR has been obsolete
since almost forever nowadays :-) I think there's a GPT command that
will copy the partitioning from a different drive. "man gdisk" or "man
fdisk" - ignore stuff that says fdisk can't do GPT, it's long been upgraded.
Okay, now you have a 2-disk mirror and a spare. Add the spare as drive 3
(ie you need (a) to add it to the array as a spare and then (b) update
the number of drives in the array to three.) You can do both in the same
command.
Monitor /proc/mdstat, which will tell you the progress of the resync.
Once you've got a fully functional 3-drive array, shut the computer
down. Swap the new drive for the old one and reboot.
/proc/mdstat will now tell you you've got a degraded 3-drive array with
one missing. fail and remove the missing drive, and you're now left with
a fully functional 2-drive array again. And at no point has your data
been at risk.
The removed drive is, as has already been said, a fully functional
backup (which is why I would recommend only removing it when the system
is shut down and you KNOW it's clean).
And I wouldn't recommend putting that drive back in the same computer,
without wiping it first! I don't think it will do any damage, but in my
experience, raid is likely to get thoroughly confused with a failed
drive re-appearing, and it's simpler not to do it. If you want to get
anything back off that drive, stick it in a different computer.
Google for "linux raid wiki". Ignore the crap about it being "obsolete"
- the admins archived a site which was aimed at end users, and are
referring people to the kernel documentation !!! Idiots !!! The two are
aimed at completely different target markets!
(How big are your drives? If they're anything like modern, there's a
very good chance they are GPT. Is the upper limit for MBR 2GB?)
Cheers,
Wol
- take i.e. /dev/sda and do
- dd bs=98304 conv=sync,noerror if=/dev/sda of=/dev/sdX (X standig for
device name of new disk)
Is it save to do it this way, presuming the array is in AA-State?
Thanks,
Steffi
/dev/sda1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 68c0c9ad:82ede879:2110f427:9f31c140
Name : speernix15:0 (local to host speernix15)
Creation Time : Sun Nov 30 19:15:35 2014
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 1953260976 (931.39 GiB 1000.07 GB)
Array Size : 976629568 (931.39 GiB 1000.07 GB)
Used Dev Size : 1953259136 (931.39 GiB 1000.07 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=261864 sectors, after=1840 sectors
State : active
Device UUID : 5871292c:7fcfbd82:b0a28f1b:df7774f9
Update Time : Thu Aug 28 01:00:03 2025
Bad Block Log : 512 entries available at offset 264 sectors
Checksum : b198f5d1 - correct
Events : 38185
Device Role : Active device 0
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdb1:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x0
Array UUID : 68c0c9ad:82ede879:2110f427:9f31c140
Name : speernix15:0 (local to host speernix15)
Creation Time : Sun Nov 30 19:15:35 2014
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 1953260976 (931.39 GiB 1000.07 GB)
Array Size : 976629568 (931.39 GiB 1000.07 GB)
Used Dev Size : 1953259136 (931.39 GiB 1000.07 GB)
Data Offset : 262144 sectors
Super Offset : 8 sectors
Unused Space : before=261864 sectors, after=1840 sectors
State : active
Device UUID : 4bbfbe7a:457829a5:dd9d2e3c:15818bca
Update Time : Thu Aug 28 01:00:03 2025
Bad Block Log : 512 entries available at offset 264 sectors
Checksum : 144ff0ef - correct
Events : 38185
