Article ID: 121929, created on Jun 7, 2014, last review on Jan 8, 2016

  • Applies to:
  • Virtuozzo 6.0


pstorage top shows Chunk total size smaller than df command:

~# pstorage -c cloud stat | grep 1070
connected to MDS#14
1070 active      782GB  294GB     7546        0     2%      0/38    0.0 6.0.6-53

As you may see pstorage top shows 782 Gb total size while df reports 825 Gb:

~# df -h /pstorage/cloud-cs1/cs
Filesystem      Size  Used Avail Use% Mounted on
/dev/sdb1       825G  451G  375G  55% /pstorage/cloud-cs1


Pstorage is running in context of an unprivileged user pstorage, not root, therefore if partition has blocks reserved for the super-user (root), the corresponding disk space won't be available for the user pstorage.

You can confirm presence of reserved blocks using following command:

~# tune2fs /dev/sdb1 | grep ^Reserved
Reserved block count:     10980531


New disks attached to and recognized by the Hardware Node need to be prepared for use in the Parallels Cloud Storage cluster by means of the /usr/libexec/pstorage/prepare_pstorage_drive tool. The tool does the following:

  1. Removes existing partitions from the disk.
  2. Creates and formats the required partition(s).

For more details, refer to the corresponding page in the documentation.

After that, manually add the new partition to "/etc/fstab". More information may be found in Cloud Storage Administration Guide.

If for some reason you do not wish to use this convinient tool, please read further.

By default mkfs creates file system with a disk space reserved for root. Default reservation size is 5%. To unlock reserved disk space you should reclaim it using following command:

# tune2fs -m 0 /dev/sdb1

In order to create file system without reservation you should append -m option to the command:

~# mkfs.ext4 /dev/sdb1 -m 0

NOTE: You should run mkfs only if you are setting up a new file system, you should never run it for existing file system.

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