Hidden properties in ZFS
I learned ZFS hides certain filesystem and pool properties from normal view. You need to know their names and specify them explicitly to get their values. Use the option -p to get the raw value of the filesystem properties. E.g. zfs get -p createtxg.
These 9 filesystem properties are hidden from normal view:
| Name | Purpose |
|---|---|
createtxg |
The birthtime transaction group (TXG) of the object. |
guid |
The globally unique identifier (GUID) of the object. |
inconsistent |
Allowed values: 0 and 1? |
iscsioptions |
? |
objsetid |
[I should re-read ch. 10 of “D&I of the FreeBSD OS, 2nd ed.”] |
name |
The object’s name. This column is usually present in a normal listing. |
numclones |
Number of clones. Set to - for normal datasets, set to ≥ 0 for snapshots. |
? |
Listed as ZFS_PROP_STMF_SHAREINFO in the source code. Could be sharenfs and sharesmb in aggregate form. |
unique |
? |
useraccounting |
Allowed values: 0 and 1? Probably tells whether the object should be considered when quota and refquota is in effect. |
These 3 pool properties are hidden from normal view:
| Name | Purpose |
|---|---|
maxblocksize |
The largest blocksize allowed in the pool. |
name |
The object’s name. This column is usually present in a normal listing. |
? |
Listed as ZPOOL_NUM_PROPS in the source code. Logic dictates this is the number of properties for each object. |
See sys/cddl/contrib/opensolaris/uts/common/sys/fs/zfs.h for more information.