up vote 1 down vote favorite

OK so I am a freelance sysadmin. I was asked to resize root partion (/) because it was 20Gb and /home was 3Tb.

What I wasn't told is that the server is using RAID and GPT, so I can't use fdisk but will have to use parted, and I don't know if RAID will come into play.

Here is all the parted, df -h, and fstab: http://pastebin.com/RFbQL0qV

Can anyone help ?

share|improve this question
    
cat /proc/mdstat will show details about the raid setup. – Nils Apr 22 '15 at 19:30
up vote 0 down vote

As you are using EXT4, it should be possible to shrink the /home/ partition. Let do an example shrinking it to about 2 TB:

  1. unmount your filesystem with umount /dev/md3
  2. check your filesystem with fsck /dev/md3
  3. resize the filesystem with resize2fs /dev/md3 1800G
  4. resize the RAID device with mdadm --grow /dev/md3 --size=1900G Please note that I left the array bigger than the underlying filesystem, by a great margin. This is because the last thing you want is to shrink too much your array, at a point where the underlying filesystem can't fit in it. This is a very bad scenario, with almost 100% guaranteed data loss.
  5. recheck your filesystem with fsck /dev/md3
  6. remount your filesystem and try to read/write to/from it.

Here you can find some other information.

Anyway, if your /dev/md3 device is almost empty, maybe destroying/recreating the array/partitions can both be easier and faster.

share|improve this answer
    
Yes, it needed mode rescue. I am backing up all files and trying it. Will update later. I prefer this solution to the other one since it doesn't require me to use parted, just resize the partition. I'll follow the same workflow for md2 and it should work [well I hope so] – thms0 Apr 23 '15 at 2:48
    
Things didn't work out the way I want.. I resized one partition and now I get "mdadm: Cannot set device size for /dev/md2: No space left on device" – thms0 Apr 23 '15 at 8:01
    
What is your current situation? Can you post your partition table setup and the likes? – shodanshok Apr 23 '15 at 8:13
    
It worked ! I rebooted, /dev/md3 493G 1.5G 466G 1% /home I will try to reboot in rescue mode and do the same thing for md2 again. /dev/root 20G 18G 219M 99% / devtmpfs 32G 4.0K 32G 1% /dev none 4.0K 0 4.0K 0% /sys/fs/cgroup none 6.3G 828K 6.3G 1% /run none 5.0M 0 5.0M 0% /run/lock none 32G 0 32G 0% /run/shm none 100M 0 100M 0% /run/user /dev/md3 493G 1.5G 466G 1% /home I am gonna boot in rescue and try agan for / – thms0 Apr 23 '15 at 8:32
    
Update 3: md3 has good block size of 600Gb from cat /proc/mdstat: 629145600 blocks [2/2] [UU] I now want to extand md2 which is 20478912 to 1887436800 but --grow=1887436800 shows no space left on device. I don't understand, really. Why no space left ?! – thms0 Apr 23 '15 at 10:11
up vote 0 down vote

This should be fun. Boot from a rescue disk and use resize2fs to shrink the /home filesystem in the raid array, then mdadm -z to shrink the size of the raid array, then mdadm -f -r to fail and remove one of the two drives from the raid arrays. Use parted on the drive you removed to delete the partitions and recreate them with the changed size you want. Then use mdadm --add to add the partition on the second drive back into the arrays, and wait for it to resync. Then fail and remove the first drive from the array, repartition the same way you did the second drive, and re-add and wait for it to resync. Finally, use mdadm -z again to increase the usable size of the root raid array, and resize2fs on it to expand the filesystem to use that space.

share|improve this answer
    
Won't that make me loose all my data ? – thms0 Apr 22 '15 at 23:12
    
@thms0, no... your data is mirrored, so the idea is to break the mirror, partition the new disk the way you want it, clone the mirror to the new disk, then clone back. The shrinking of the volume is done offline and safely using resize2fs and mdadm to shrink the fs and raid array. – psusi Apr 23 '15 at 1:49
    
Ho, thanks for the explanation. – thms0 Apr 23 '15 at 2:41
up vote 0 down vote

OK, just seen your answers, thanks everyone for your input. Right now, I am gonna do a NFS and rsync -avPH to do a full backup of the system. Also saved the full packages list that are installed. I will try your solution, if it fails I will reinstall and just rsync back.

I'll update later.

Thanks a lot for answering, anyway :).

share|improve this answer

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.