Setting space reservations for files

What space reservations are

When space reservations are enabled for files, Data ONTAP reserves enough space in the volume so that writes to the file do not fail because of a lack of disk space (ENOSPC error). Other operations such as snapshots or the creation of new files can occur only if there is enough available space; they are restricted from using reserved space.

Writes to new or existing unreserved space in a volume will fail when the total amount of free space in the volume is less than the amount needed according to the current reserve values. Once free space goes below this value, only writes to reserved space will succeed and are guaranteed to succeed.

File space reservations are persistent across filer reboots and across takeovers and givebacks, but do not persist through reversions to an earlier software version.

Enabling space reservations for files

To enable space reservations for a file, complete the following step.

Step	Action
1	Enter the following command: *file reservation file_name* [overwrite\|fill] [enable\| disable]** file_name is the file in which file reservations are to be set. This must be an existing file. `enable` turns space reservations on for the file in file_name. `disable` turns space reservations off for the file in file_name. `fill` enables space reservations only to fill holes in file_name. `overwrite` enables space reservations only to overwrite blocks that have already been written in filename. Specifying `file reservation enable` or `disable` without specifying `fill` or `overwrite` turns both options on or off. Examples file reservation myfile enable file reservation myfile enable overwrite file reservation myfile disable fill

Step

Action

Enter the following command:

file reservation file_name [overwrite|fill] [enable| 
disable]

file_name is the file in which file reservations are to be set. This must be an existing file.

enable turns space reservations on for the file in file_name.

disable turns space reservations off for the file in file_name.

fill enables space reservations only to fill holes in file_name.

overwrite enables space reservations only to overwrite blocks that have already been written in filename.

Specifying file reservation enable or disable without specifying fill or overwrite turns both options on or off.

Examples



file reservation myfile enable

file reservation myfile enable overwrite

file reservation myfile disable fill

Turning on space reservation for a file will fail if there is not enough free space in the volume for the new reservation.

Querying space reservations for files

To find out the status of space reservations for files in a volume, complete the following step.

Step	Action
1	Enter the following command: *file reservation file_name* overwrite or file reservation file_name fill** file_name is the file for which space reservations are set. Example file reservation myfile fill