1: # ZFS on NetBSD
3: This page attempts to do two things: provide enough orientatino and
4: pointers to standard ZFS documentation for NetBSD users who are new to
5: ZFS, and to to describe NetBSD-specific ZFS information. It is
6: emphatically not a tutorial or an introduction to ZFS.
8: Many things are marked with \todo because they need a better
9: explanation, and some have question marks, indicating that the
10: statement needs verification.
12: # Documentation Pointers
14: See the man pages for zfs(8) and zpool(8).
16: - [Oracle ZFS Administration Manual](https://docs.oracle.com/cd/E26505_01/html/E37384/index.html)
17: - [FreeBSD Handbook ZFS Chapter](https://www.freebsd.org/doc/handbook/zfs.html)
19: # Status of ZFS in NetBSD
21: NetBSD has imported OpenZFS. \todo versions, links
23: ## NetBSD 8 and earlier
25: While there is some ZFS code, it is old, and seems to have significant
26: problems. If one wants to use ZFS, first upgrade to NetBSD 9. It is
27: unlikely that anyone is interested in helping, other than telling you
28: to upgrade to 9.
30: (Reports of how well NetBDS 8 works are welcome on netbsd-users, if it
31: can actually be recommended for use.)
33: ## NetBSD 9
35: There have been fixes since 9.0 RELEASE. It is best to upgrade along
36: the netbsd-9 branch, but the release should be ok.
38: \todo This is OpenZFS as of X. Most aspects work solidly.
40: \todo This supports pool version 28/5000 (really true?). Of the
41: feature flags found in modern OpenZFS, \todo are supported.
43: Generally, fixes to ZFS in current will be pulled up to 9, but new
44: features typically will not be.
46: ## NetBSD current
48: The ZFS code in current is very similar to that in 9.
50: There is initial support for [[ZFS root|wiki/RootOnZFS]], via booting from
51: ffs and pivoting.
53: One can make a ccd using a zvol as a component. This allows reading a
54: GPT label from the zvol, which is useful in case the zvol had been
55: exported via iscsi and some other system created a label.
57: ## things that aren't suported yet
59: \todo hotswap (maybe - not clear exactly what this means)
61: \todo direct boot into zfs root (via bootblocks reading zfs)
63: ## Architectures
65: Most people seem to be using amd64.
67: To build zfs, one puts MKZFS=yes in mk.conf. This is default on amd64
68: and aarch64 on netbsd-9. In current, it is also default on sparc64.
70: More or less, zfs can be enabled on an architecture when it is known
71: to build and run reliably. (Of course, users are welcome to build it
72: and report.)
74: # NetBSD-specific information
76: ## rc.conf
78: The main configuration is to put zfs=YES in rc.conf, so that the rc.d
79: scripts bring up ZFS and mount ZFS filesystems.
81: ## legacy vs ? mount points
83: \todo Explain, if this is NetBSD specific. Explain consequences, as
84: this seems to have something to do with mount ordering.
86: ## mount order
88: NetBSD 9 mounts other filesystems and then ZFS filesystems. This can
89: be a problem if /usr/pkgsrc is on ZFS and /usr/pkgsrc/distfiles is on
90: NFS. A workaround is to use noauto and do the mounts in
93: NetBSD current after 20200301 mounts ZFS first. \todo Explain
96: ## TRIM
98: There is some notion of TRIM and zfs using it.
100: \todo Explain how this relates to NetBSD.
102: # Memory usage
104: Basically, ZFS uses lots of memory and most people run it on systems
105: with large amounts of memory. NetBSD works well on systems with
106: comparatively small amounts of memory. So a natural question is how
107: well ZFS works on one's VAX with 2M of RAM :-)
109: More seriously, one might ask if is reasonable to run ZFS on a RPI3
110: with 1G of RAM, or even if it is reasonable on a system with 4G.
112: \todo Give ballpark level for minimum sane RAM, and the amount which
113: is cleanly enough.
115: For now, a good guess is that a 4G system with only 1T of disk is
116: probably ok, 1G is very likely not ok.
118: FreeBSD has some documentation about memory use. There is a notion of
119: a minimum of 1G, and using 1G for 1T of storage, and more if
120: deduplication is enabled. FreeBSD considers all i386 systems to be
121: low memory; this appears to be a clue.
123: \todo Explain if the FreeBSD sysctl list applies, or if not what we
124: should do instead.
126: - [FreeBSD low memory documentation](https://www.freebsd.org/doc/handbook/zfs-advanced.html)
128: # Interoperability with other systems
130: \todo Explain pool version and feature flags relationship to FreeBSD,
131: Linux, OpenIndiana/Illumos/?, and ?
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