1: # ZFS on NetBSD
3: This page attempts to do two things: provide enough orientation and
4: pointers to standard ZFS documentation for NetBSD users who are new to
5: ZFS, and 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)
18: - [OpenZFS admin docs index page](https://github.com/openzfs/zfs/wiki/Admin-Documentation)
20: - https://en.wikipedia.org/wiki/ZFS
22: # Status of ZFS in NetBSD
24: ## Sources of ZFS code
26: \todo Verify/fix.
28: Currently, there are multiple ZFS projects and codebases:
30: - ZFS as released under the CDDL (common ancestor)
31: - [OpenZFS](http://www.open-zfs.org/wiki/Main_Page) [github wiki](https://github.com/openzfs/zfs/wiki)
32: - [zfsonlinux](https://zfsonlinux.org/)
33: - [OpenZFS on OS X ](https://openzfsonosx.org/) [repo](https://github.com/openzfsonosx)
34: - proprietary ZFS in Solaris (not relevant in open source)
36: OpenZFS is a coordinating project to align open ZFS codebases. There
37: is a notion of a shared core codebase and OS-specific adaptation code.
39: - [zfsonlinux relationship to OpenZFS](https://github.com/openzfs/zfs/wiki/OpenZFS-Patches)
41: \todo Explain clearly the relationship between OpenZFS and zfsonlinux,
42: and also the Illumos and OSX versions.
44: See [FreeBSD's history](https://wiki.freebsd.org/ZFSTuningGuide).
46: ## NetBSD code history
48: \todo This section really needs help.
50: Before NetBSD 8, NetBSD imported ZFS code from ?, which was version ?
52: Before NetBSD 9, NetBSD imported updated ZFS code from FreeBSD. That
53: FreeBSD code came from ?, which was version ?
55: ## NetBSD 8 and earlier
57: While there is some ZFS code, it is old, and seems to have significant
58: problems. If one wants to use ZFS, first upgrade to NetBSD 9. It is
59: unlikely that anyone is interested in helping, other than telling you
60: to upgrade to 9.
62: (Reports of how well NetBSD 8 works are welcome on netbsd-users, if it
63: can actually be recommended for use.)
65: ## NetBSD 9
67: There have been fixes since 9.0 RELEASE. It is best to upgrade along
68: the netbsd-9 branch, but the release should be ok. Most aspects work solidly.
70: \todo Explain this in terms of versions of FreeBSD OpenZFS and/or
73: \todo This supports pool version 28/5000 (really true?). Of the
74: feature flags found in modern OpenZFS, \todo are supported.
76: Generally, fixes to ZFS in current will be pulled up to 9, but new
77: features typically will not be.
79: ## NetBSD current
81: The ZFS code in current is very similar to that in 9.
83: There is initial support for [[ZFS root|wiki/RootOnZFS]], via booting from
84: ffs and pivoting.
86: One can make a ccd using a zvol as a component. See the zvol section below.
88: ## Things that aren't supported yet
90: \todo hotswap (maybe - not clear exactly what this means)
92: \todo direct boot into zfs root (via boot blocks reading zfs)
94: ## Architectures
96: Most people seem to be using amd64.
98: To build zfs, one puts MKZFS=yes in mk.conf. This is default on amd64
99: and aarch64 on netbsd-9. In current, it is also default on sparc64.
101: More or less, zfs can be enabled on an architecture when it is known
102: to build and run reliably. (Of course, users are welcome to build it
103: and report.)
105: # NetBSD-specific information
107: ## rc.conf
109: The main configuration is to put zfs=YES in rc.conf, so that the rc.d
110: scripts bring up ZFS and mount ZFS file systems.
112: ## pool locations
114: One can add disks or parts of disks into pools. Methods of specifying
115: areas to be included include:
117: - entire disks (e.g., /dev/rwd0d on amd64)
118: - disklabel partitions (e.g., /dev/sd0e)
119: - wedges (e.g., /dev/dk0)
121: ## legacy vs ? mount points
123: \todo Explain, if this is NetBSD specific. Explain consequences, as
124: this seems to have something to do with mount ordering.
126: ## mount order
128: NetBSD 9 mounts other file systems and then ZFS file systems. This can
129: be a problem if /usr/pkgsrc is on ZFS and /usr/pkgsrc/distfiles is on
130: NFS. A workaround is to use noauto and do the mounts in
133: NetBSD current after 20200301 mounts ZFS first. \todo Explain
136: ## NFS
138: \todo Verify if this is accurate.
140: zfs filesystems can be exported over NFS. While there are zfs
141: commands that appear to be about controlling exports, they simply
142: print information that can be added to exports(5).
144: This is reported to work on 9.0 STABLE, but to cause a panic on
145: current (20200302).
147: ## zvol
149: Within a ZFS pool, the standard approach is to have file systems, but
150: one can also create a zvol, which is a block device of a certain size.
152: \todo The zvol will appear as /dev/???? and can be used in many
153: respects like a slice. However, the system will not read disklabels
154: and gpt labels from a zvol; in this respect it is more like a disklabel
155: partition or wedge than a disk drive.
157: \todo Explain that one can export a zvol via iscsi.
159: \todo Explain if one can swap on a zvol.
161: \todo Explain that one can use ccd to create a normal-looking disk
162: from a zvol. This allows reading a GPT label from the zvol, which is
163: useful in case the zvol had been exported via iscsi and some other
164: system created a label.
166: ## TRIM
168: There is some notion of TRIM and zfs using it.
170: \todo Explain how this relates to NetBSD.
172: # Memory usage
174: Basically, ZFS uses lots of memory and most people run it on systems
175: with large amounts of memory. NetBSD works well on systems with
176: comparatively small amounts of memory. So a natural question is how
177: well ZFS works on one's VAX with 2M of RAM :-)
179: More seriously, one might ask if it is reasonable to run ZFS on a RPI3
180: with 1G of RAM, or even if it is reasonable on a system with 4G.
182: \todo Give ballpark level for minimum sane RAM, and the amount which
183: is cleanly enough.
185: For now, a good guess is that a 4G system with only 1T of disk is
186: probably ok, and that 1G is very likely not ok.
188: FreeBSD has some documentation about memory use. There is a notion of
189: a minimum of 1G (used for ZFS), and using 1G for 1T of storage, and
190: more if deduplication is enabled. FreeBSD considers all i386 systems
191: to be low memory; this appears to be a clue.
193: \todo Explain if the FreeBSD sysctl list applies, or if not what we
194: should do instead.
196: - [FreeBSD low memory documentation](https://www.freebsd.org/doc/handbook/zfs-advanced.html)
198: # Interoperability with other systems
200: \todo Explain pool version and feature flags relationship to FreeBSD,
201: Linux, OpenIndiana/Illumos/?, and ?
203: \todo Explain how to configure a pool in terms of version/features for
204: use with particula other systems.
206: # Quick Start
208: See the [FreeBSD Quickstart
209: Guide](https://www.freebsd.org/doc/handbook/zfs-quickstart.html); only
210: the first item is NetBSD specific.
212: - Put zfs=YES in rc.conf.
214: - Create a pool as "zpool create pool1 /dev/dk0".
216: - df and see /pool1
218: - Really, read the FreeBSD docs and the other linked documentation above.
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