Recovery of ZVOL timestamps

To the best of my understanding, ZFS ZVOLs do not have their own timestamps (stored reasonably close to the ZVOL itself).

Omitting timestamps is quite reasonable, as ZVOL is intended to be a container for another filesystem. That filesystem tracks its own timestamps. So there is no need to have timestamps for the ZVOL container, in the same way as a hard drive does not track its last write time.

Klennet Recovery, however, does provide timestamps for the recovered ZVOLs. These timestamps are derived from the transaction numbers and are thus approximate. Most of the pools have some kind of a file-based dataset (for example, application datasets in TrueNAS). These datasets do track timestamps and thus provide the information to cross-reference transaction numbers with wall clock time. Klennet Recovery interpolates these cross-references to provide the estimated timestamps for ZVOLs.

Filed under: ZFS.

Created Wednesday, March 4, 2026