adding raid 1 to existing server. ( what next)

[tross9]

I'm adding a raid 1 to my existing server, i'm going to be using the current sdb as a backup drive and want to have raid 1 on it.
--
current server info:
sda - ( boot drive ) -- no raid
ata disk
160 MB
Partioned partioned : dos
sdb - ( share drive) -- no raid -- samba for window access -- to allow backup of windows system files to sdb drive. ( docs, pics, etc..)
ata disk
1tb
Partioned partioned : dos
--
where i am with the server:
added second 1tb drive (sdc) as is and did not do anything else to it.
so drives are now, lshw -- sees all three drive ( as listed )

sda - ( boot drive ) -- no raid
ata disk
160 MB
Partioned partioned : dos
sdb - ( share drive) -- no raid -- samba for window access
ata disk
1tb
Partioned partioned : dos

sdc - (was from windows 7 system -- still format as a windows drive -- still has Window 7 OS and other data -- I do not need)
ata disk
1tb
Partioned partioned : dos

--
status so far:

Tested sdc by -- mkdir /media/drive and mounting /dev/sdc -- got msgs (wrong FS type bad option ....)
but cd to drive and
df command did show two lines
root root .
root root ..

--
question :

1) do I need to format sdc? or will the Madam command take care of it? ( i assume that sdc will be written over, and to the same format as sdb, yes? no?)
2) I assume all I need to run is the following (only?)
sudo madam --create --verbose /dev/md0 --force --level=1 --raid-device=1 /dev/sdb ( some examples show /dev/sdb1 do i need the number?)
sudo madam --grow /dev/md0 --raid-device=2 --add /dev/sdc ( again do i need to add a number)

i assume the --grow will overwrite the format on the sdc drive to match sdb.

3) do i need to change the auto mount param, ( it is currently mounting sdb as /media/drivesdb on boot up)
or do i need to tell the system to mount the raid ( edit fstab to add /media/drivesdb /dev/md0 or edit the exist entry, or do nothing)



Tia
Tim

[darkod]

Hold on. You have couple of big mistakes...

Most important, if sdb curently has the data you need, you don't start by creating the array with sdb. You do it with the new disk, sdc.

And yes, it is better to have a number, like /dev/sdc1, because that means partition #1. It is better to use partitions for mdadm even though it can work with disk designator like /dev/sdc.

Also, you will create the array as 2 disk raid1 array, with one disk missing. That allows you to simplify things and you avoid doing grow later.

So your first step is to create new partition table on sdc to remove the current ntfs partitions. You said you DON'T need the data, right??? I don't know which tool you prefer, I myself prefer parted in the command line. And even though it is not necessary for a disk of 1TB, it is preferred to use gpt table, no msdos.

It is also best to check total number of MiB that sdb and sdc have. The disks are 1TB but the exact number of MiB might differ slightly. This is why I create the partition to end around 15-20MiB before the end of the disk. That way it allows new disk in the future to be able to have a partition of the same size.

You can check total number of MiB and other basic data of each disk with:

sudo parted /dev/sdb unit MiB print
sudo parted /dev/sdc unit MiB print

[SeijiSensei]

I would create a single partition on each of sdb and sdc. I use fdisk for this task so I can mark the partitions as type "fd" which is the code for RAID component.

This will obviously destroy all the data on both drives.

Next you would create a RAID1 array using mdadm (not "madam"):

sudo mdadm /dev/md0 --create --level=1 --raid-devices=2 /dev/sdb1 /dev/sdc1

Then you can format the array with whatever filesystem you need. For a standard ext4 Linux filesystem, you'd use

sudo mkfs -t ext4 /dev/md0

Then specify a mount point in the filesystem and add the array to /etc/fstab. I'd use "sudo blkdid" to find its "UUID", then use the UUID in /etc/fstab.

[tross9]

Thanks darkod And SeijiSensei

i did not mention that I backup the SDB drive and if I loose the data on SDB, i have it else where.

i'll be using both of your suggestions to create my raid. i hope to have it created soon.

again thanks.


Tim

[rsteinmetz70112]

Assuming you get the partition sdc1 right you can make it a 2 disk raid 1 array with a missing disk, copy everything on to sdc1 then repartition sdb and add sdb1 to the array you set up.

[tross9]

sdc1 is a 1TB drive. ( so is sdb1)

Question,

when running fdisk /dev/sdc1
I enter n them p
the following is displayed


device size type ( i think it said type)
/dev/sdc1p1 835.5g qnx4. ...
/dev/sdc1p2 259.6g unknown
/dev/sdc1p3 259.5g unknown
/dev/sdc1p4 26.9m speedstor

I assume that these are the window partition, that were leftover, and the Px are the partition number
do I want to have one partition for my raid or will Mdadm fix that? ( or do I delete the partitions first then create a new partition on sdc1)
also do I need repartition sdb1? ( seeing that it is ext4 already)

fdisk -l
shows
sdb1 as 1 device 931.5 in size and Linux lvm
sdc1 as 1 device 931.5 in size and hpfs/ntfs/exfat ( I assume I need to have it changed to Linux lvm)

Thank you

[darkod]

You need to repartition any disk that was used before. You want it to be with new clean partition table, like new. So that means you need to repartition both sdb and sdc.

You might have sdb1 as ext4 right now, but with mdadm the sdb1 does not carry any filesystem. The filesystem will be on the raid array device, like /dev/md0.

You can use fdisk or parted, which ever you prefer. But start by creating new empty gpt partition table. Of course, this will destroy all data on both disks but you said you are OK restoring that from backups.

I still think best approach is to create the array with sdc1 and one member missing, copy the data from current sdb1, then repartition sdb to add the new sdb1 to the array. From internal to internal HDD it would copy the data much faster.

If your backup is on external USB for example, copying back from it would take much longer than from internal HDD.

But the choice how you handle this operation is on you.

[tross9]

ok,
when I tried to create a new partition on /dev/sdc1

fdisk displayed the following,


device size type ( i think it said type)
/dev/sdc1p1 835.5g qnx4. ...
/dev/sdc1p2 259.6g unknown
/dev/sdc1p3 259.5g unknown
/dev/sdc1p4 26.9m speedstor

so do I delete the existing partition first? then create a new single partition?

sorry about not knowing the steps to take, still new to Ubuntu.

[TheFu]

I saw a number of questions asked above which still haven't been answered. Commands run.

Tip: If you'd like good help, answer the questions. Run the commands. Post the output.

Tip: Don't interpret the output. Just post it WITH THE EXACT COMMAND RUN.

Tip: whenever posting commands and output, use forum code-tags so it looks like it did in the terminal. This is a simple copy/paste thing. Nobody is asking for any extra work, no font changes, nothing like that. https://ubuntuforums.org/misc.php?do=bbcode#code

Please.

[SeijiSensei]

ok,
when I tried to create a new partition on /dev/sdc1

fdisk displayed the following,

device size type ( i think it said type)
/dev/sdc1p1 835.5g qnx4. ...
/dev/sdc1p2 259.6g unknown
/dev/sdc1p3 259.5g unknown
/dev/sdc1p4 26.9m speedstor

In fdisk, "d(elete)" all the partitions, then use "n(ew)" to create a new partition that spans the entire disk. Use the "t(ype)" command to mark it as type "fd". Then "w(rite)" the results to the drive. Do the same to the other disk to be used in the array. Then run mdadm --create to bind the partitions together.