Use 2nd (Second) drive as backup drive

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syssu

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Apr 23, 2011
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OK I have searched both google and this forum but have found some stuff close to what I need but not an exact answer. First Id like to state that I'm very new to the linux environment so I need a step-by-step guidance to complete this task.

What I have setup is a computer with 2 hard drives. 1 is a 1TB drive and another is a 2TB drive. Everything is currently installed on the 1TB drive and I would like to use the 2nd 2TB drive as strictly for backups. So far I know the following;

- 2TB (that i want to use for backup) is /dev/sda
- 1TB (with everything install on as of now) is /dev/sdb
- I created a 2nd LVM and added the 2TB drive but in the proxmox disk setup I can only choose to use it vm disks and not as backups.

Thank you in advance!
 
syssu said:
OK I have searched both google and this forum but have found some stuff close to what I need but not an exact answer. First Id like to state that I'm very new to the linux environment so I need a step-by-step guidance to complete this task.

What I have setup is a computer with 2 hard drives. 1 is a 1TB drive and another is a 2TB drive. Everything is currently installed on the 1TB drive and I would like to use the 2nd 2TB drive as strictly for backups. So far I know the following;

- 2TB (that i want to use for backup) is /dev/sda
- 1TB (with everything install on as of now) is /dev/sdb
- I created a 2nd LVM and added the 2TB drive but in the proxmox disk setup I can only choose to use it vm disks and not as backups.

Thank you in advance!
Click to expand...
Hi,
you are sure that your pve-installation is on sdb? Normaly the first disk - sda is used!

For backup you need a filesystem. lvm give you space for logical volumes (which can contains filesystem, or raw-devices or whatever).
You have two choices.
1. remove lvm from second disk and create a normal (e.g. ext4) filesystem (partition-type 83).
2. (which i prefer) simply create an logical volume on your lvm for backup - this has the effort you can play also with VM-disks on lvm, because you don't need to use all space for backup in the beginning - logical volumes can grow whithout trouble.

For 2:
Code: 
lvcreate -L 1T -n backup name_of_VG    # create an logical volume with 1TB on the volumegroup name_of_VG

#have a look:
vgdisplay
lvdisplay

mkfs.ext4 /dev/name_of_VG/backup
mkdir /backup
echo "/dev/name_of_VG/backup /backup ext4 defaults 0 2" >> /etc/fstab     # appends this line to fstab
mount /backup
after that, define the directory /backup as backup-storage.

To expand the logical volume see "man lvm", "man lvextend" and "man resize2fs".

Udo
 
you are sure that your pve-installation is on sdb? Normaly the first disk - sda is used!
Click to expand...
That is what I thought too and i tripple checked it because it was so confusing and did not match anything I read on the internet. But if I do an fdisk /dev/sdb it shows <1000GB and if i do fdisk /dev/sda it shows 2000GB meaning it has to be that way...also I just put in the 2TB drive today, after the install. It also said it was a GPT partition on the /dev/sda from when it was in my mac...

let me try what you have listed and ill report back, thank you!
 
OK, I did the command vgdisplay and got this for the 2nd LVM i created with the 2TB drive.


Code: 
--- Volume group ---
  VG Name               second-lvm
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               1
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               1.82 TB
  PE Size               4.00 MB
  Total PE              476932
  Alloc PE / Size       204800 / 800.00 GB
  Free  PE / Size       272132 / 1.04 TB
  VG UUID               tWCzBC-V2Wl-gduN-zNcJ-WGQF-F9PD-FaKkxf

So i tried to run the following line and got the following error. any ideas?

Code: 
proxmox:~# mkfs.ext4 /dev/second-lvm/backup
mke2fs 1.41.3 (12-Oct-2008)
Could not stat /dev/second-lvm/backup --- No such file or directory

The device apparently does not exist; did you specify it correctly?
 
syssu said:
OK, I did the command vgdisplay and got this for the 2nd LVM i created with the 2TB drive.


Code: 
--- Volume group ---
  VG Name               second-lvm
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                1
  Open LV               1
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               1.82 TB
  PE Size               4.00 MB
  Total PE              476932
  Alloc PE / Size       204800 / 800.00 GB
  Free  PE / Size       272132 / 1.04 TB
  VG UUID               tWCzBC-V2Wl-gduN-zNcJ-WGQF-F9PD-FaKkxf
So i tried to run the following line and got the following error. any ideas?

Code: 
proxmox:~# mkfs.ext4 /dev/second-lvm/backup
mke2fs 1.41.3 (12-Oct-2008)
Could not stat /dev/second-lvm/backup --- No such file or directory

The device apparently does not exist; did you specify it correctly?
Click to expand...
Hi,
about sda and sdb:
you installed with only one hdd (thats ok). the first hdd is sda. After that you put the second hdd, but at the device-order (on the bus) the second hdd is before the pve-hdd, so after reboot the pve-hdd became sdb.
Perhaps you can change the order in the bios, or switch the slot. Its better to be sure, that grub installed on the right hdd.

about lvm:
please give the output of
Code: 
lvdisplay
ls -l /dev/mapper

Udo
 
udo said:
Hi,
about sda and sdb:
you installed with only one hdd (thats ok). the first hdd is sda. After that you put the second hdd, but at the device-order (on the bus) the second hdd is before the pve-hdd, so after reboot the pve-hdd became sdb.
Perhaps you can change the order in the bios, or switch the slot. Its better to be sure, that grub installed on the right hdd.
Click to expand...

If i change it back to how it is suppose to be will that mess up anything?

udo said:
about lvm:
please give the output of
Code: 
lvdisplay
ls -l /dev/mapper

Udo
Click to expand...

Sorry took so long i was asleep
Code: 
proxmox:~# ls -l /dev/mapper
total 0
crw-rw---- 1 root root  10, 62 Apr 22 13:53 control
brw-rw---- 1 root disk 254,  2 Apr 22 13:53 pve-data
brw-rw---- 1 root disk 254,  1 Apr 22 13:53 pve-root
brw-rw---- 1 root disk 254,  0 Apr 22 13:53 pve-swap
brw-rw---- 1 root disk 254,  3 Apr 22 21:00 second--lvm-vm--102--disk--1
 
syssu said:
If i change it back to how it is suppose to be will that mess up anything?
Click to expand...
Hi,
changing back should be not a problem. Because, the lvm-volumes finds itself and /boot is assign with UUID.
Sorry took so long i was asleep
Code: 
proxmox:~# ls -l /dev/mapper
total 0
crw-rw---- 1 root root  10, 62 Apr 22 13:53 control
brw-rw---- 1 root disk 254,  2 Apr 22 13:53 pve-data
brw-rw---- 1 root disk 254,  1 Apr 22 13:53 pve-root
brw-rw---- 1 root disk 254,  0 Apr 22 13:53 pve-swap
brw-rw---- 1 root disk 254,  3 Apr 22 21:00 second--lvm-vm--102--disk--1
Click to expand...
ahh,
you dont have a lv named backup - only a disk of the vm with the VMID 102.
I guess, there wasn't enough free space to create the backup-lv.
But with "vgdisplay" you see the free space... but it's show 1.04TB - should fit... perhaps something else wrong?
try this to use most of the space:
Code: 
lvcreate -l 270000 -n backup /dev/second-lvm
One disadvantage has the solution with Backup and VM-lvm on one lvm: you can run in trouble with backup in snapshot-mode, because both on the same lvm...

Udo
 
I deleted the disk for the VM and removed the lvm from proxmox and now it says for the 2tb drive...notice the free space

Code: 
  --- Volume group ---
  VG Name               second-lvm
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  5
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               1.82 TB
  PE Size               4.00 MB
  Total PE              476932
  Alloc PE / Size       0 / 0   
  Free  PE / Size       476932 / 1.82 TB
  VG UUID               tWCzBC-V2Wl-gduN-zNcJ-WGQF-F9PD-FaKkxf

So what do I need to type to get the backup running now? also the ls-l/dev/mapper now displays the following

Code: 
proxmox:~# ls -l /dev/mapper
total 0
crw-rw---- 1 root root  10, 62 Apr 23 17:56 control
brw-rw---- 1 root disk 254,  2 Apr 23 17:56 pve-data
brw-rw---- 1 root disk 254,  1 Apr 23 17:56 pve-root
brw-rw---- 1 root disk 254,  0 Apr 23 17:56 pve-swap

Thank you in advance!
 
syssu said:
I deleted the disk for the VM and removed the lvm from proxmox and now it says for the 2tb drive...notice the free space

Code: 
  --- Volume group ---
  VG Name               second-lvm
  System ID             
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  5
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                0
  Open LV               0
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               1.82 TB
  PE Size               4.00 MB
  Total PE              476932
  Alloc PE / Size       0 / 0   
  Free  PE / Size       476932 / 1.82 TB
  VG UUID               tWCzBC-V2Wl-gduN-zNcJ-WGQF-F9PD-FaKkxf
So what do I need to type to get the backup running now? also the ls-l/dev/mapper now displays the following

Code: 
proxmox:~# ls -l /dev/mapper
total 0
crw-rw---- 1 root root  10, 62 Apr 23 17:56 control
brw-rw---- 1 root disk 254,  2 Apr 23 17:56 pve-data
brw-rw---- 1 root disk 254,  1 Apr 23 17:56 pve-root
brw-rw---- 1 root disk 254,  0 Apr 23 17:56 pve-swap
Thank you in advance!
Click to expand...
Hi,
have you tried my example before?

lvcreate -l 270000 -n backup /dev/second-lvm
ls -l /dev/mapper
mkfs.ext4 /dev/second-lvm/backup
Click to expand...
Udo
 
I did not try it before because I was not sure if everything would still apply seeing how I ade the changes. I went ahead and ran it and everything seemed to turn out just fine on the SSH end but what do I need to do to create the backups part on proxmox?

For example i tried to go to storage>Add LVM, but it does not show the backups one i created.
 
syssu said:
I did not try it before because I was not sure if everything would still apply seeing how I ade the changes. I went ahead and ran it and everything seemed to turn out just fine on the SSH end but what do I need to do to create the backups part on proxmox?

For example i tried to go to storage>Add LVM, but it does not show the backups one i created.
Click to expand...

Had to run the last little bit of commands

Code: 
mkdir /backup
echo "/dev/name_of_VG/backup /backup ext4 defaults 0 2" >> /etc/fstab     # appends this line to fstab
mount /backup

One thing I noticed is it only takes up around 985GB of space for the backup, is that because of the command lvcreate -l 270000 -n backup /dev/second-lvm and what in the command made it do that so i can understand what is going on.
 
syssu said:
Had to run the last little bit of commands

Code: 
mkdir /backup
echo "/dev/name_of_VG/backup /backup ext4 defaults 0 2" >> /etc/fstab     # appends this line to fstab
mount /backup
One thing I noticed is it only takes up around 985GB of space for the backup, is that because of the command lvcreate -l 270000 -n backup /dev/second-lvm and what in the command made it do that so i can understand what is going on.
Click to expand...
Hi,
with "-l" you give the amount of logical extends - in your case one extend is 4MB in size.
Look with "vgdisplay" how much do you have free. You can use "lvextend -l +XXXX" for extends, or "-L +800M" for MB.
After that use simply resize2fs.
Do an "df -k" before and after that.

Udo
 
Thank you very much you were very helpful! Looks like everything is setup and running. Ill know at 00:00 24 hours if it worked for sure, thank you again!
 
I used udo’s Option 1 and did the following and it worked.
For Dummies like me I’ve put it in as simple english as possible.

#Identify local disk to be used as backup drive via proxmox ssh console
fdisk -l
# In our case dev/sdc was intended for the local backup drive.

# format and prepare disk for mounting
cfdisk /dev/sdc
create Primary partition and Write and Quit
mkfs.ext4 /dev/sdc1
# don’t forget the number 1 at the end of the command or you will be banging your head on the desk for several hours wondering why its not working

# Manually mount disk to test that it can be mounted
mount -t ext4 /dev/sdc1 /mnt/backup

# goto proxmox web interface to setup local proxmox backup directory
Select Datacenter folder
Select Storage tab
Click Add | Directory
ID: local_backup_2TB (note - this can be what ever you want it to be)
Directory: /mnt/backup
Content: Backups
OK

# Go back to ssh console to configure backup disk to mount automatically on boot:
nano /etc/fstab

#append following to fstab file (note lines starting with # are used for comments and are ignored)
# automount internal 2TB backup disk
/dev/sdc1 /mnt/backup ext4 defaults 0 2

Ctrl-X to quit and Y to save changes

Reboot to test that you can see the local_backup_2TB Directory in web interface and that directory Status is Active
 
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