Maintain volumes using Filesystem Trim
A typical Portworx volume is formatted with either ext4 or xfs and then used by a container application to store its content files and directories. Over time, your application might create and delete files and directories. On the volume, the space which was previous used by a deleted file gets freed in the filesystem metadata and the underlying block device is unaware of this fact. This can lead to the following inefficiencies:
- On thin provisioned volumes, the freed space in the volume does not translate into free space in the pool. This means that other volumes in the pool that require space might not be able to get it from the pool.
- On SSDs, the block device performs better when it has knowledge of all the freed blocks that the user no longer requires. This information is used by the SSD firmware to perform wear-leveling more efficiently to improve the service life of the storage device and also provide better I/O performance. When the information about the blocks freed in the filesystem is not available to the block device, it creates hot spots in the device that cause it to wear more than rest of the blocks in the device.
To address these inefficiencies, you can instruct the filesystem to inform the block device of all the unused blocks which were previously used by issuing a FITRIM
ioctl to the mounted filesystem. The filesystem in turn issues a DISCARD request for the freed blocks to the block device.
Perform a filesystem trim operation
Open a shell session with the Portworx node on which the volume you intend to run the filesystem trim operation on is mounted.
Enter the
pxctl volume trim start
command with the--path
flag and your mount path and volume name to start the filesystem trim operation on a volume:```text pxctl volume trim start --path <mount_path> <volume_name> ```
Monitor the filesystem trim operation running on a volume by entering the
pxctl volume trim status
command with the--path
flag and your mount path and volume name:```text pxctl volume trim status --path <mount_path> <volume_name> ```
Stop a filesystem trim operation
Stop a running filesystem trim operation by entering the pxctl volume trim status
command with the --path
flag and your mount path and volume name:
```text
pxctl volume trim stop --path <mount_path> <volume_name>
```
pxctl volume trim reference
pxctl volume trim start
pxctl volume trim start --path <mount_path> <volume_name>
Description
Start a filesystem trim operation on the block device and volume you specify
Arguments
| <volume_name>
| The name of the volume on which you want to perform a filesystem trim operation |
Flags
| --path
| Use this flag to provide the mount path where the volume/device is mounted <mount_path>
|
Examples
Start a filesystem trim operation on an example volume:
```text pxctl volume trim start --path /mnt/pxd/mount/path exampleVolume ```
pxctl volume trim status
pxctl volume trim status --path <mount_path> <volume_name>
Description
Display the status of a currently running filesystem trim operation on the block device and volume you specify
Arguments
| <volume_name>
| The name of the volume you want to see the currently running filesystem trim operation status for |
Flags
| --path
| Use this flag and specify the path reference to the mount point or mount directory where the volume is mounted. |
Examples
Show the status for a running filesystem trim operation on an example volume:
```text pxctl volume trim status --path /mnt/pxd/mount/path exampleVolume ```
pxctl volume trim stop
pxctl volume trim stop --path <mount_path> <volume_name>
Description
Stop a currently running filesystem trim operation on the block device and volume you specify
Arguments
| <volume_name>
| The name of the volume for which you want to stop a filesystem trim operation |
Flags
| --path
| Use this flag and specify the path reference to the mount point or mount directory where the volume is mounted, for example: /var/lib/osd/examplevolume
. |
Examples
Stop the running filesystem trim operation on an example volume:
```text pxctl volume trim stop --path /mnt/pxd/mount/path exampleVolume ```