Aug 192002

Growing your filesystem with growfs

This article was written by Will Andrews.
Copyright (c) 2002 Will Andrews <>. All rights reserved.

The Story

I needed more disk space on my vinum volume, which I created about 18 months ago using 2 IBM DeskStar 30GXP 30GB ATA100 drives. Originally, I created a RAID 0 (stripe) filesystem on top of these drives using vinum. But now I needed more disk space for various processes that I was running on the machine. So I got a new IBM DeskStar 80GB ATA100 drive. Just like the FreeBSD diary article on vinum, I had an /etc/vinum.conf. Its contents were:

drive drive1 device /dev/ad4s1e
drive drive2 device /dev/ad6s1e
 volume firepipe
  plex org concat
    sd length 29314m drive drive1
    sd length 29314m drive drive2
The result was a ~55GB vinum volume. Starting with FreeBSD 4.4, a new command, called growfs(8), was introduced which allows one to grow (but not shrink) a filesystem. It was particularly designed to work with vinum, but also works on normal filesystems.

The problem and the solution

Not being exactly sure how to format the new disk, I visited the FreeBSD documentation link suggested by the Diary’s vinum page and read the details on how to create a “dangerously dedicated” (the original drives on the plex were sliced by sysinstall) disk. Once that was done, all I had to do was change /etc/vinum.conf to this:
drive drive1 device /dev/ad4s1e
drive drive2 device /dev/ad6s1e
drive drive3 device /dev/ad0e
 volume firepipe
  plex org concat
    sd length 29314m drive drive1
    sd length 29314m drive drive2
    sd length 78355m drive drive3
Then I rebooted the system to single user mode, and did this:
# vinum resetconfig
Type 'NO FUTURE' as is necessary.  This will destroy the previous
configuration on the vinum volume.

# vinum create -f /etc/vinum.conf
[..some vinum output..]

# growfs /dev/vinum/firepipe
Growfs(8) will ask whether the filesystem is backed up. NOTE: Backing up the filesystem is HIGHLY recommended. I did this *BEFORE* touching the new drive or the RAID filesystem. Growfs(8) will then proceed to extend the filesystem and it will give an output similar to newfs(8), in that it prints the locations of the superblocks. Note, however, that these are *new* superblocks on the filesystem, as they are being placed on the *new* drive. Once this process finishes, the system should be able to mount the filesystem with the additional disk space.

  5 Responses to “Growing your filesystem with growfs”

  1. It’s quite unnecessary to obliterate the whole vinum config. Since you already have a volume with a concatenated plex you can just add another subdisk to this plex and then run growfs on top of it.

    • fine and you can tell me the way???

      i have had problems vinum had sayed
      i use my drive with 200%, and the attachement
      from a new generated subdisk have many errors

      The way described in this article has gone fine and
      relatively easy, easier then the other with errors.

      once growfs have taked a long time for the "growing" ;-))


      sorry for my bad english


  2. I ran growfs to expand a file system. growfs ran OK but it printed "Nothing changed" when it finished. I had to use the -y flag to get growfs to actually do something. Fun stuff.

    • Are you shure, that the volume is correctly configured
      and not mounted, vinum started??

      i have ran growfs on the growed volume from me and
      he says we not growing (bs->bs)

      where bs is the size of this volume..

  3. hi,

    first i thanks to the author, that he has tested
    this critical mission.

    i have yesterday at night reconfigure my big
    concatenated volume.

    it was a little bit tricky and critical for
    the data on the volume, may it work’s

    an i find this is a great thing,
    vinum have not the tools and the comfort
    like the veritas volumemanager, may it is stable.

    so long… have fun and use FreeBSD….