1: # ZFS on NetBSD
2:
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.
7:
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.
11:
12: # Documentation Pointers
13:
14: See the man pages for zfs(8) and zpool(8).
15:
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)
19:
20: - https://en.wikipedia.org/wiki/ZFS
21:
22: # Status of ZFS in NetBSD
23:
24: ## Sources of ZFS code
25:
26: \todo Verify/fix.
27:
28: Currently, there are multiple ZFS projects and codebases:
29:
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)
35:
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.
38:
39: \todo Explain clearly the relationship between OpenZFS and zfsonlinux,
40: and also the Illumos and OSX versions.
41:
42: See [FreeBSD's history](https://wiki.freebsd.org/ZFSTuningGuide).
43:
44: ## NetBSD code history
45:
46: \todo This section really needs help.
47:
48: Before NetBSD 8, NetBSD imported ZFS code from ?
49:
50: Before NetBSD 9, NetBSD imported updated ZFS code from FreeBSD. That
51: FreeBSD code came from ?
52:
53: ## NetBSD 8 and earlier
54:
55: While there is some ZFS code, it is old, and seems to have significant
56: problems. If one wants to use ZFS, first upgrade to NetBSD 9. It is
57: unlikely that anyone is interested in helping, other than telling you
58: to upgrade to 9.
59:
60: (Reports of how well NetBSD 8 works are welcome on netbsd-users, if it
61: can actually be recommended for use.)
62:
63: ## NetBSD 9
64:
65: There have been fixes since 9.0 RELEASE. It is best to upgrade along
66: the netbsd-9 branch, but the release should be ok. Most aspects work solidly.
67:
68: \todo Explain this in terms of versions of FreeBSD OpenZFS and/or
69: zfsonlinux.
70:
71: \todo This supports pool version 28/5000 (really true?). Of the
72: feature flags found in modern OpenZFS, \todo are supported.
73:
74: Generally, fixes to ZFS in current will be pulled up to 9, but new
75: features typically will not be.
76:
77: ## NetBSD current
78:
79: The ZFS code in current is very similar to that in 9.
80:
81: There is initial support for [[ZFS root|wiki/RootOnZFS]], via booting from
82: ffs and pivoting.
83:
84: One can make a ccd using a zvol as a component. See the zvol section below.
85:
86: ## Things that aren't supported yet
87:
88: \todo hotswap (maybe - not clear exactly what this means)
89:
90: \todo direct boot into zfs root (via boot blocks reading zfs)
91:
92: ## Architectures
93:
94: Most people seem to be using amd64.
95:
96: To build zfs, one puts MKZFS=yes in mk.conf. This is default on amd64
97: and aarch64 on netbsd-9. In current, it is also default on sparc64.
98:
99: More or less, zfs can be enabled on an architecture when it is known
100: to build and run reliably. (Of course, users are welcome to build it
101: and report.)
102:
103: # NetBSD-specific information
104:
105: ## rc.conf
106:
107: The main configuration is to put zfs=YES in rc.conf, so that the rc.d
108: scripts bring up ZFS and mount ZFS file systems.
109:
110: ## pool locations
111:
112: One can add disks or parts of disks into pools. Methods of specifying
113: areas to be included include:
114:
115: - entire disks (e.g., /dev/rwd0d on amd64)
116: - disklabel partitions (e.g., /dev/sd0e)
117: - wedges (e.g., /dev/dk0)
118:
119: ## legacy vs ? mount points
120:
121: \todo Explain, if this is NetBSD specific. Explain consequences, as
122: this seems to have something to do with mount ordering.
123:
124: ## mount order
125:
126: NetBSD 9 mounts other file systems and then ZFS file systems. This can
127: be a problem if /usr/pkgsrc is on ZFS and /usr/pkgsrc/distfiles is on
128: NFS. A workaround is to use noauto and do the mounts in
129: /etc/rc.local.
130:
131: NetBSD current after 20200301 mounts ZFS first. \todo Explain
132: consequences.
133:
134: ## NFS
135:
136: \todo Verify if this is accurate.
137:
138: zfs filesystems can be exported over NFS. While there are zfs
139: commands that appear to be about controlling exports, they simply
140: print information that can be added to exports(5).
141:
142: This is reported to work on 9.0 STABLE, but to cause a panic on
143: current (20200302).
144:
145: ## zvol
146:
147: Within a ZFS pool, the standard approach is to have file systems, but
148: one can also create a zvol, which is a block device of a certain size.
149:
150: \todo The zvol will appear as /dev/???? and can be used in many
151: respects like a slice. However, the system will not read disklabels
152: and gpt labels from a zvol; in this respect it is more like a disklabel
153: partition or wedge than a disk drive.
154:
155: \todo Explain that one can export a zvol via iscsi.
156:
157: \todo Explain if one can swap on a zvol.
158:
159: \todo Explain that one can use ccd to create a normal-looking disk
160: from a zvol. This allows reading a GPT label from the zvol, which is
161: useful in case the zvol had been exported via iscsi and some other
162: system created a label.
163:
164: ## TRIM
165:
166: There is some notion of TRIM and zfs using it.
167:
168: \todo Explain how this relates to NetBSD.
169:
170: # Memory usage
171:
172: Basically, ZFS uses lots of memory and most people run it on systems
173: with large amounts of memory. NetBSD works well on systems with
174: comparatively small amounts of memory. So a natural question is how
175: well ZFS works on one's VAX with 2M of RAM :-)
176:
177: More seriously, one might ask if it is reasonable to run ZFS on a RPI3
178: with 1G of RAM, or even if it is reasonable on a system with 4G.
179:
180: \todo Give ballpark level for minimum sane RAM, and the amount which
181: is cleanly enough.
182:
183: For now, a good guess is that a 4G system with only 1T of disk is
184: probably ok, and that 1G is very likely not ok.
185:
186: FreeBSD has some documentation about memory use. There is a notion of
187: a minimum of 1G (used for ZFS), and using 1G for 1T of storage, and
188: more if deduplication is enabled. FreeBSD considers all i386 systems
189: to be low memory; this appears to be a clue.
190:
191: \todo Explain if the FreeBSD sysctl list applies, or if not what we
192: should do instead.
193:
194: - [FreeBSD low memory documentation](https://www.freebsd.org/doc/handbook/zfs-advanced.html)
195:
196: # Interoperability with other systems
197:
198: \todo Explain pool version and feature flags relationship to FreeBSD,
199: Linux, OpenIndiana/Illumos/?, and ?
200:
201: \todo Explain how to configure a pool in terms of version/features for
202: use with particula other systems.
203:
204: # Quick Start
205:
206: See the [FreeBSD Quickstart
207: Guide](https://www.freebsd.org/doc/handbook/zfs-quickstart.html); only
208: the first item is NetBSD specific.
209:
210: - Put zfs=YES in rc.conf.
211:
212: - Create a pool as "zpool create pool1 /dev/dk0".
213:
214: - df and see /pool1
215:
216: - Really, read the FreeBSD docs and the other linked documentation above.
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