resize2fs: Bad magic number in super-block while trying to open ….

Posted on June 17, 2015 by Juergen Caris

… or how to resize a file system on CentOS 7. Due to moving my home partition to a new disk I gained some space back from the logical volume home. After deleting it I thought that it would be a good idea to add those additional 10GB to the my root disk.
I started with:

[root@jcdesk Desktop]# lvdisplay
--- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                jxyjgx-veql-Hzxk-1ynz-b6i2-BQoe-xGhrCb
  LV Write Access        read/write
  LV Creation host, time jc-desk.luht.scot.nhs.uk, 2015-06-11 ....
  LV Status              available
  # open                 1
  LV Size                105.00 GiB
  Current LE             26879
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

The size of the root volume was 105GiB. The additional space should be 10GiB.

[root@jcdesk Desktop]# lvextend -l +100%FREE /dev/centos/root
  Size of logical volume centos/root changed from 105.00 GiB 
(26879 extents) to 115.00 GiB (29440 extents).
  Logical volume root successfully resized

That added all the free space in the volume group to my root volume.

[root@jcdesk ~]# lvdisplay /dev/centos/root
  --- Logical volume ---
  LV Path                /dev/centos/root
  LV Name                root
  VG Name                centos
  LV UUID                jxyjgx-veql-Hzxk-1ynz-b6i2-BQoe-xGhrCb
  LV Write Access        read/write
  LV Creation host, time jc-desk.luht.scot.nhs.uk, 2015-06-11 ...
  LV Status              available
  # open                 1
  LV Size                115.00 GiB
  Current LE             29440
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0

Strike !!! So far so good. Now lets resize the file system.

[root@jcdesk Desktop]# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root  105G  7.0G   98G   7% /

I tried to resize the file system to the new size.

[root@jcdesk Desktop]# resize2fs /dev/mapper/centos-root
resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in super-block while trying to open 
/dev/mapper/centos-root
Couldn't find valid filesystem superblock.

Oops !!!!! 8-o
I took me a while to find out that LVM is using xfs as their file system.

[root@jcdesk ~]# mount | grep centos-root
/dev/mapper/centos-root on / type xfs (rw,relatime,...

Xfs comes with its own command set.

[root@jcdesk ~]# xfs [tab][tab]
xfs_admin      xfs_copy       xfsdump        xfs_freeze     
xfs_growfs     xfsinvutil     xfs_logprint   xfs_metadump   
xfs_ncheck     xfs_repair     xfs_rtcp     xfs_bmap       
xfs_db         xfs_estimate   xfs_fsr      xfs_info       
xfs_io         xfs_mdrestore  xfs_mkfile     xfs_quota      
xfsrestore

So instead of using the resize2fs command I had to use the xfs_growfs command.

[root@jcdesk ~]# xfs_growfs /dev/mapper/centos-root
meta-data=/dev/mapper/centos-root isize=256 agcount=4, agsize=
6881024 blks
         =              sectsz=512   attr=2, projid32bit=1
         =              crc=0        finobt=0
data     =              bsize=4096   blocks=27524096, imaxpct=25
         =              sunit=0      swidth=0 blks
naming   =version 2     bsize=4096   ascii-ci=0 ftype=0
log      =internal      bsize=4096   blocks=13439, version=2
         =              sectsz=512   sunit=0 blks, lazy-count=1
realtime =none          extsz=4096   blocks=0, rtextents=0
data blocks changed from 27524096 to 30146560

A final check:

[root@jcdesk ~]# df -h
Filesystem               Size  Used Avail Use% Mounted on
/dev/mapper/centos-root  115G  7.0G  108G   7% /

….. done.

About Juergen Caris

I am 54yo, MSc(Dist) and BSc in Computer Science, German and working as a Senior Server Engineer for the NHS Lothian. I am responsible for the patient management system, called TrakCare. I am a UNIX/Linux guy, working in this sector for more than 20 years now. I am also interested in robotics, microprocessors, system monitoring, Home automation and programming.
This entry was posted in Beginner, Linux. Bookmark the permalink.

50 Responses to resize2fs: Bad magic number in super-block while trying to open ….

  1. adison says:
    August 28, 2015 at 02:08

    Thanks, you saved my friday and weekend

    Reply
    • Hui says:
      November 12, 2020 at 02:00

      Thanks, this blog is super helpful! It hit the nails and resolved my issue on Veteran’s Day.

      Another way to find out the type is to run blkid command.
      [root@msdlva-ctwwik01 appdev]# blkid /dev/mapper/rhel-root
      /dev/mapper/rhel-root: UUID=”xxx” TYPE=”xfs”

      [root@wik01 appdev]# mount | grep root
      /dev/mapper/rhel-root on / type xfs (rw,noatime,nodiratime,attr2,inode64,noquota)

      Reply
  2. Robert Plant says:
    September 24, 2015 at 20:23

    Many thanks Juergen! I was stumbling at resize2fs and quickly found your post allowing me to complete my partition resizing.

    Many kudo!
    Robert

    Reply
  4. deepthi says:
    December 21, 2015 at 04:40

    Thanks a lot,very helpfull

    Reply
  5. deo says:
    February 1, 2016 at 09:32

    Thank you!

    Reply
  6. kamal Chikh echioukh says:
    February 22, 2016 at 14:28

    Many thanks, very helpfull… it saves me time…

    Reply
  7. Denzi Junaidi says:
    March 15, 2016 at 08:09

    Thanks for your tutorial..

    Reply
  8. ifaii says:
    April 5, 2016 at 02:49

    thanks, so good!

    Reply
  9. Dave Fouts says:
    April 13, 2016 at 08:44

    Looked everywhere.. thanks for that info.. did not see xfs_growfs anywhere.

    Reply
  10. bernie says:
    April 14, 2016 at 12:13

    Thanks.
    Exactly what I was looking for…

    Reply
  11. Chris says:
    June 13, 2016 at 21:55

    phew thanks for posting this!

    Reply
  13. sergei says:
    November 11, 2016 at 17:56

    Thank you for your solution! I was in panic because I didn’t understand what is wrong (I’m new in system administration). Thank you very much for this post:)

    Reply
  14. Slava says:
    November 17, 2016 at 10:46

    Thanks, it worked! Was trying to resolve the issue for hours…

    Reply
  15. jongbyte says:
    January 12, 2017 at 11:32

    you saved my day thank you so much i was stuck here until i found out of xfs.thanks again cheers!

    Reply
  16. Vinodh says:
    February 3, 2017 at 19:19

    Thanks a lot for sharing, worked for my CentOS7 VM image.

    Reply
  17. Eitan says:
    February 16, 2017 at 07:26

    Thanks for the post !

    Reply
  18. Jose says:
    February 17, 2017 at 17:29

    Thanks man you saved my life hahahah

    Reply
  19. Reginaldo Ramos says:
    March 8, 2017 at 22:16

    Saved my job, fantastic … thank you very much.

    Reply
  20. kennedy says:
    April 20, 2017 at 14:13

    Thanks for the post

    Reply
  21. Mario says:
    April 26, 2017 at 21:30

    Excelent!!!

    Thanks I take the same problem and solved thanks to you.

    Reply
  22. Gino says:
    July 1, 2017 at 21:22

    Thank you man, this saved my evening! 🙂

    Reply
  23. Imran says:
    August 3, 2017 at 18:03

    Hi,
    Thanks. This was a lifesaver 🙂

    Reply
  24. Maulana says:
    August 18, 2017 at 06:43

    Many thank’s

    Solved my problem

    Reply
  25. Tiago Rocha says:
    August 31, 2017 at 19:54

    Perfect!!!

    Thanks!!!

    Reply
  26. sandeep says:
    February 6, 2018 at 04:50

    Thanks a lot,very helpfull

    Reply
  27. Alex says:
    February 12, 2018 at 13:07

    Perfect Thank you very much!

    Reply
  28. Francesco Montani says:
    March 12, 2018 at 17:15

    Thanks a lot! In 2018 your post continue to help someone…ME…. 🙂

    Reply
  29. Palash says:
    May 3, 2018 at 11:04

    Thanks, Great Help 🙂

    Reply
  30. Pavel Perna says:
    June 27, 2018 at 15:20

    Great, finally a worthy solution. You saved my day

    Reply
  31. Nuno Nabo says:
    July 21, 2018 at 20:42

    Perfect!!! You save my weekend!!! Thanks a lot!!!

    Reply
  32. Chok says:
    July 26, 2018 at 16:41

    Great ! solve my problem.

    Reply
  33. Y V Ravi Kumar says:
    August 5, 2018 at 18:01

    Saved my Evening Brother !!! Good solution

    Reply
  34. Andrea says:
    October 10, 2018 at 14:16

    Thanks…..my idol

    Reply
  35. inger says:
    December 14, 2018 at 20:11

    Thank you for this, I got some info from Amazon while trying to grow a root disk but the advice was based on their Amazon Linux AMI that used a different filesystem type and boy howdy, was _that_ a scary error message to get!

    Reply
  36. Dominique says:
    January 9, 2019 at 13:05

    Many thanks for this post !

    Reply
  37. djcarlos2001 says:
    February 25, 2019 at 14:05

    Very helpful post, many thanks.

    Reply
  38. Alvaro says:
    March 28, 2019 at 20:47

    Gracias, excelente informacion

    Reply
  39. Paola says:
    April 1, 2019 at 08:58

    Thanks so much!!!!

    Reply
  40. Hard DM says:
    April 12, 2019 at 15:14

    Thx a lot

    Reply
  41. flavio nascimento says:
    May 19, 2019 at 02:54

    he was save me

    Reply
  42. Victor Nyakutya says:
    July 26, 2019 at 23:21

    I was also stranded.
    The post did wonders for me.
    Thanks a lot

    Reply
  43. Allen Bell says:
    September 20, 2019 at 16:00

    Thank you so much! I had beem struggling with this for hours!

    Reply
  44. Suryakant says:
    November 26, 2019 at 09:09

    Hi,

    Thank you so much for your help. XFS works in a different way

    Reply
  45. Bui says:
    February 3, 2020 at 07:09

    Thanks so much!!

    Reply
  46. Gireesh Tangudu says:
    April 22, 2020 at 22:05

    Thank you very much….it saved my day

    Reply
  47. Tahsin Mutlu says:
    April 25, 2020 at 21:07

    Thank you so much. You’re save me 🙂

    Reply
  48. Xavier Automation says:
    January 28, 2021 at 19:23

    Merci infiniment ça m’a beaucoup aidé !

    Reply
  49. Bill Silvester says:
    August 10, 2021 at 15:15

    Many thanks for your post – saved a lot of frustration!

    Reply

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