MDADM - How can I add a disk and expand my array?

[HyRax1]

Originally Posted by -Sk3tChY-

Could it be the fact my server isn't very powerful? (It's a HP Microserver with 1GB RAM)

CPU power does play a part, and the Microserver isn't exactly the beefiest of servers.

But like I said before, you'll get a marked improvement in build speed if you take all the mounted filesystems on that array offline.

[-Sk3tChY-]

admin@server:~$ cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sda1[4] sdd1[2] sde1[3] sdc1[1] sdb1[0]
      5860535808 blocks super 0.91 level 5, 64k chunk, algorithm 2 [5/5] [UUUUU]
      [==================>..]  reshape = 91.5% (1788903728/1953511936) finish=988.0min speed=2776K/sec

unused devices: <none>

ALMOSTT!!!!!!@!@!@@111!

[-Sk3tChY-]

admin@server:~$ sudo cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md0 : active raid5 sda1[4] sdd1[2] sde1[3] sdc1[1] sdb1[0]
      7814047744 blocks level 5, 64k chunk, algorithm 2 [5/5] [UUUUU]

unused devices: <none>

Everything looks to have completed?

I tried doing a little research on pvresize and lvresize like Hyrax said and am not sure where to start?

I tried foloowing this guide and didn't get too far.

When I do this:

admn@server:~$ sudo vgdisplay Array
  --- Volume group ---
  VG Name               Array
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  4
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               3
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               5.46 TiB
  PE Size               4.00 MiB
  Total PE              1430794
  Alloc PE / Size       1430794 / 5.46 TiB
  Free  PE / Size       0 / 0
  VG UUID               6fFfbz-tT9X-pYYh-iimO-KkEp-SlsI-mjQ3LO

It shows no Free PE / Size? Does this mean the disk wasn't added properly? Or have I missed something?

[elvis]

Originally Posted by -Sk3tChY-

It shows no Free PE / Size? Does this mean the disk wasn't added properly? Or have I missed something?

If your PV is sitting inside a partition, you need to resize the partition first.

The "pvresize" command with no size arguments will resize a PV to the full size of either the partition on block device it's sitting on.

[-Sk3tChY-]

Originally Posted by elvis

If your PV is sitting inside a partition, you need to resize the partition first.

The "pvresize" command with no size arguments will resize a PV to the full size of either the partition on block device it's sitting on.

Could you elaborate a little please?

What would the PV be? /dev/md0?

Would I need to issue:

pvresize /dev/md0

[HyRax1]

PV = Physical Volume (on a partition)
LV = Logical Volume (on a PV)

Partition must be made bigger to made PV bigger, which in turn must be bigger to make LV bigger.

[f3n1x]

Originally Posted by -Sk3tChY-

Could you elaborate a little please?

What would the PV be? /dev/md0?

Would I need to issue:

pvresize /dev/md0

you can list any PV's you have on the system with

# pvdisplay

if you're having trouble understanding the relationships between block devices,PVs,VGs and LVs, i suggest reading through this:
http://www.redhat.com/magazine/009jul05/features/lvm2/

[-Sk3tChY-]

Originally Posted by HyRax1

PV = Physical Volume (on a partition)
LV = Logical Volume (on a PV)

Partition must be made bigger to made PV bigger, which in turn must be bigger to make LV bigger.

What's confusing me right now about this is that my PV appears to be on /dev/md0:

admin@server:~$ sudo pvdisplay
[sudo] password for admin:
  --- Physical volume ---
  PV Name               /dev/md0
  VG Name               Array
  PV Size               5.46 TiB / not usable 3.50 MiB
  Allocatable           yes (but full)
  PE Size               4.00 MiB
  Total PE              1430794
  Free PE               0
  Allocated PE          1430794
  PV UUID               S9aCm8-cagB-xelg-tfgL-UZXz-KI5x-y3GbYa

I thought that by adding the disk to md0 I was essentially making the "partition" bigger? Then I could make the PV bigger, then the LV bigger.

What am I missing?

Originally Posted by f3n1x

if you're having trouble understanding the relationships between block devices,PVs,VGs and LVs, i suggest reading through this:
http://www.redhat.com/magazine/009jul05/features/lvm2/

Thanks for that link! I think I've grasped some of the concepts a little better, but still unsure on how to apply them technically.

[HyRax1]

That link explains everything nicely. Nothing more needs to be said.

[-Sk3tChY-]

root@server: resize2fs /dev/mapper/Array-Home
resize2fs 1.41.11 (14-Mar-2010)
Filesystem at /dev/mapper/Array-Home is mounted on /home; on-line resizing required
old desc_blocks = 349, new_desc_blocks = 465
Performing an on-line resize of /dev/mapper/Array-Home to 1948141568 (4k) blocks.

Approx how long will this take? It doesn't show any progress bar or anything.

I had a friend give me a hand, hopefully after this resize the array will be expanded. Thanks for the help Hyrax, elvis and others.

[elvis]

Run "watch df -h" in another terminal and you'll see the size of the mounted partition grow in real time.

You can run that as a non-root account (no admin/root/sudo access needed).

[-Sk3tChY-]

Originally Posted by elvis

Run "watch df -h" in another terminal and you'll see the size of the mounted partition grow in real time.

Thanks elvis.

Really noob question here; how do I get another terminal?

I vaguely remember Linux having the ability to run like, multiple user sessions at once. I'm not sure what the proper name for it is, but essentially you press something like CTRL+F* and it gives you multiple shells from like F2-F9.

Is this what you meant?

Originally Posted by elvis

You can run that as a non-root account (no admin/root/sudo access needed).

The mate that helped me runs Gentoo or something, I don't think it has sudo? He chose to log in as root, I normally just use sudo coz I'm noob and don't want to break something.

[elvis]

Originally Posted by -Sk3tChY-

how do I get another terminal?

Either SSH in a second time, or if you're at the physical console hit ALT+F2 to go to the second virtual terminal (and ALT+F1 to go back to the first).

You can use up to F6, as F7 and above are reserved for X11.

[HyRax1]

Originally Posted by -Sk3tChY-

The mate that helped me runs Gentoo or something, I don't think it has sudo? He chose to log in as root, I normally just use sudo coz I'm noob and don't want to break something.

The "sudo" command means "superuser do", which means "execute this next command as root". This is no different to running the same command in a root shell. Some people simply don't like adding "sudo" to the front of every root-required command, so they run a root shell instead to save some keystrokes (you know, because keyboards have a limited-stroke warranty on them).

The root account is disabled by default in Ubuntu, however You can get a root shell in Ubuntu easily enough by typing in "sudo bash" and you'll see the dollar sign replaced with a hash which indicates root, but this is potentially dangerous if you accidentally enter a wrong command that could trash part or all of your system so I'd advise you stay as an unprivileged user (the dollar sign) and execute root commands only as needed with the "sudo" prefix.

[-Sk3tChY-]

Thanks for the help guys, as always I appreciate it.

I just took another look at the server and the file system expansion looks to have completed without a hitch:

The filesystem on /dev/mapper/Array-Home is now 1948141568 blocks long.

Then did a df -h as suggested by elvis and /dev/mapper/Array-Home looks to have expanded succesfully:

admin@server:~$ df -h
Filesystem            Size Used Avail Use% Mounted on
/dev/mapper/Array-Root
                       19G  1.3G   17G   8% /
none                  431M  212K  431M   1% /dev
none                  436M     0  436M   0% /dev/shm
none                  436M  2.1M  434M   1% /var/run
none                  436M     0  436M   0% /var/lock
none                  436M     0  436M   0% /lib/init/rw
/dev/mapper/Array-Home
                      7.2T  4.1T  3.0T  58% /home

Took a look at my share from a windows machine and it has also expanded to 7.14TB!

I am a very happy camper now.