How to Increase swap space in a CentOS VM

Question

While trying to RPM install Oracle XE in a CentOS 7 VM running inside Virtualbox 5.1 I get the following error message:

This system does not meet the minimum requirements for swap space.  Based on
the amount of physical memory available on the system, Oracle Database 11g
Express Edition requires 2048 MB of swap space. This system has 1279 MB
of swap space.  Configure more swap space on the system and retry the 
installation.

How can I increase the swap space?

So far I have tried with lvm following the instructions here and here without success. I must start with an already provisioned minimal CentOS VM so tweaking the original image is not an option.

A swapon -s command informs me:

Filename                Type        Size    Used    Priority
/dev/dm-1               partition   1310716 0       -1

and lvdisplay output is:

  --- Logical volume ---
  LV Path                /dev/cl/swap
  LV Name                swap
  VG Name                cl
  LV UUID                rdNgH4-Sili-NpwP-Ny3S-xtU9-MlEC-ttE5JI
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2016-12-19 22:50:56 +0000
  LV Status              available
  # open                 2
  LV Size                1.25 GiB
  Current LE             320
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:1

  --- Logical volume ---
  LV Path                /dev/cl/root
  LV Name                root
  VG Name                cl
  LV UUID                H737Lq-OMhE-F9Lf-BlTg-3PL1-0T7O-1Ciusi
  LV Write Access        read/write
  LV Creation host, time localhost.localdomain, 2016-12-19 22:50:56 +0000
  LV Status              available
  # open                 1
  LV Size                12.39 GiB
  Current LE             3172
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     8192
  Block device           253:0

and df -h

Filesystem           Size  Used Avail Use% Mounted on
/dev/mapper/cl-root   13G  9.4G  3.1G  76% /
devtmpfs             907M     0  907M   0% /dev
tmpfs                920M  4.0K  920M   1% /dev/shm
tmpfs                920M  8.7M  912M   1% /run
tmpfs                920M     0  920M   0% /sys/fs/cgroup
/dev/sda1           1014M  239M  776M  24% /boot
tmpfs                184M     0  184M   0% /run/user/1002
tmpfs                184M     0  184M   0% /run/user/1001
tmpfs                184M   12K  184M   1% /run/user/1000
tmpfs                184M     0  184M   0% /run/user/2
/dev/sr0              57M   57M     0 100% /run/media/vagrant/VBOXADDITIONS_5.1.33_120529
vagrant              102G   77G   26G  76% /vagrant

Edit:

Content of /etc/fstab

/dev/mapper/cl-root     /                       xfs     defaults        0 0
UUID=41388da5-fc65-4a34-a3da-58bb81daf744 /boot                   xfs     defaults        0 0
/dev/mapper/cl-swap     swap                    swap    defaults        0 0

Output of vgs

VG #PV #LV #SN Attr   VSize  VFree
cl   1   2   0 wz--n- 13.64g 4.00m

Solution 1

These are the steps for both swap (the question) or a normal partition.

When logical volumes (LVM) are concerned, ignore answers you may find on the Internet about using gparted to resize partitions - but why would you when you have logical volumes? Instead we're gonna make an extra new partition and extend our logical volume to include it.

In VirtualBox, open the Virtual Media Manager. Find the related *.vdi file and ensure its Virtual Size is big enough for the extra space you want, slightly larger because the filesystem-structures need space. For the rest of this example we're gonna choose 64GB of extra space, so in this step I'll arbitrarily choose 65G.

Then, in your CentOS VM:

1. Find the '/dev/mapper/?' entry of the logical volume you're expanding. For swap use sudo fdisk -l, but for enlarging normal mount-points it's easier to use df -h and look at Filesystem. The rest of this example we'll pretend it was '/dev/mapper/cl-root'.
2. Use sudo lsblk to find the drive (actually your vdi) that the volume lives on. For this example I'll pretend it was '/dev/sda'.
3. sudo fdisk /dev/sda. Use commands n (add partition) then p(primary). Accept all the defaults but for "Last sector" enter our choice of +64G, or accept its default if you want all remaining space. Use commands w to write and quit. Reboot if asked.
4. In the last step we made a new partition, so if you hadn't rebooted then add that to the /dev table. Eg. pvcreate /dev/sda3. You may now be asked to reboot for the kernel to use the new table, so do it.
5. sudo vgscan to learn the name of the Volume Group. In the question it is 'cl'
6. Allow/extend the Volume Group to include the partition we made: sudo vgextend cl /dev/sda3
7. Get your intended logical volume to use the amount we want from it: sudo lvextend -L +64G /dev/mapper/cl-root. If it can't fit what you desire, it'll nicely tell you the max 'extents' and you can instead use sudo lvextend -l [extents] /dev/mapper/cl-root
8. Skip this step for swap. Expand the filesystem into that area. For ext4 you'll need resize2fs, for xfs you'll need sudo xfs_growfs /dev/mapper/cl-root

Solution 2

You can increase your swap space by first shrinking the root logical volume to free up space, which you can then reallocate to the swap logical volume. You need to increase your swap LV by 769 MB to get it up to 2048 MB, and your root LV has 3.1 GB free, so you can try the following:

1. Shrink your root LV. The -r option causes the filesystem to be resized as well: lvresize -L -769M -r c1/root
2. Temporarily turn off your swap, since you're going to be modifying it: swapoff
3. Resize your swap LV. Alternatively, delete it and recreate it using contiguous allocation so that the physical extends are adjacent to each other for potentially better performance: lvresize -L +769M c1/swap
4. Turn swap back on: swapon

Solution 3

This is what I had to do:

With the VM halted, add a new virtual hard disk from Virtualbox by right clicking on the machine and then Configuration -> Storage. Click on the icon of a hard drive with a + sign and add a new disk of 2Gb fixed size.

After adding the new hard disk start the machine and once logged in type:

sudo vgdisplay

this will display the volume group information showing something like: VG Name cl

Then execute

sudo fdisk -l

to list the available drives. You should get in the list /dev/hdb or /dev/sdb depending on whether you are using spinning or solid states physical drives.

Now execute:

sudo pvcreate /dev/sdb
sudo vgextend cl /dev/sdb
sudo lvextend -L+2G /dev/cl/swap

this will add 2Gb to the swap space.

Comments

[fpmurphy]

Please provide contents of /etc/fstab

[Atul Vekariya]

Add new LV and create it swap. And provide the output of vgs command

[Serg M Ten]

I added /etc/fstab and vgs. I think my first problem is VFree=4.00m right? Because all the available disk space is already taken I can't grow the swap file.

[fpmurphy]

I seem to recall that Oracle XE requires a swap file of at least twice the size of memory. How much memory have you configured for your VM?

[Raman Sailopal]

You will need to add another disk to the virtual guest from hard drive space on the host. This disk will then need adding to the volume group on the guest and then allocated to the swap logical volume

[Serg M Ten]

Thanks @emmanuel-rosa This would be a very good solution. Unfortunately, when I try lvresize -L -769M -r /dev/mapper/cl-root I get fsadm: Xfs filesystem shrinking is unsupported and according to this reply it is impossible to shrink an XFS filesystem. SO I guess I'll have no ther choice than following @raman-sailopal advise and add another disk :(