Space guarantees on a FlexVol volume ensure that writes to a specified FlexVol volume or writes to files with space reservations enabled do not fail because of lack of available space in the containing aggregate.
Space guarantee is an attribute of the volume. It is persistent across storage system reboots, takeovers, and givebacks. Space guarantee values can be volume (the default value), file, or none.
- A space guarantee of volume reserves space in the aggregate for the volume. The reserved space cannot be allocated to any other volume in that aggregate.
The space management for a FlexVol volume that has a space guarantee of volume is equivalent to a traditional volume.
- A space guarantee of file reserves space in the aggregate so that any file in the volume with space reservation enabled can be completely rewritten, even if its blocks are being retained on disk by a Snapshot copy.
- A FlexVol volume that has a space guarantee of none reserves no extra space for user data; writes to LUNs or files contained by that volume could fail if the containing aggregate does not have enough available space to accommodate the write.
Note: Because out-of-space errors are unexpected in a CIFS environment, do not set space guarantee to none for volumes accessed using CIFS.
When space in the aggregate is reserved for space guarantee for an existing volume, that space is no longer considered free space. Operations that consume free space in the aggregate, such as creation of Snapshot copies or creation of new volumes in the containing aggregate, can occur only if there is enough available free space in that aggregate; these operations are prevented from using space already committed to another volume.
When the uncommitted space in an aggregate is exhausted, only writes to volumes or files in that aggregate with space guarantees are guaranteed to succeed.
Note: Space guarantees are honored only for online volumes. If you take a volume offline, any committed but unused space for that volume becomes available for other volumes in that aggregate. When you bring that volume back online, if there is not sufficient available space in the aggregate to fulfill its space guarantees, you must use the force (-f) option, and the volume’s space guarantees are disabled. When a volume's space guarantee is disabled, the word (disabled) appears next to its space guarantees in the output of the vol status command.
