File:  [NetBSD Developer Wiki] / wikisrc / zfs.mdwn
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zfs: fix linkn

    1: # ZFS on NetBSD
    2: 
    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.
    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: 
   19: # Status of ZFS in NetBSD
   20: 
   21: NetBSD has imported OpenZFS.  \todo versions, links
   22: 
   23: ## NetBSD 8 and earlier
   24: 
   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.
   29: 
   30: (Reports of how well NetBDS 8 works are welcome on netbsd-users, if it
   31: can actually be recommended for use.)
   32: 
   33: ## NetBSD 9
   34: 
   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.
   37: 
   38: \todo This is OpenZFS as of X.   Most aspects work solidly.
   39: 
   40: \todo This supports pool version 28/5000 (really true?).  Of the
   41: feature flags found in modern OpenZFS, \todo are supported.
   42: 
   43: Generally, fixes to ZFS in current will be pulled up to 9, but new
   44: features typically will not be.
   45: 
   46: ## NetBSD current
   47: 
   48: The ZFS code in current is very similar to that in 9.
   49: 
   50: There is initial support for [[ZFS root|wiki/RootOnZFS]], via booting from
   51: ffs and pivoting.
   52: 
   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.
   56: 
   57: ## things that aren't suported yet
   58: 
   59: \todo hotswap (maybe - not clear exactly what this means)
   60: 
   61: \todo direct boot into zfs root (via bootblocks reading zfs)
   62: 
   63: ## Architectures
   64: 
   65: Most people seem to be using amd64.
   66: 
   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.
   69: 
   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.)
   73: 
   74: # NetBSD-specific information
   75: 
   76: ## rc.conf
   77: 
   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.
   80: 
   81: ## legacy vs ? mount points
   82: 
   83: \todo Explain, if this is NetBSD specific.  Explain consequences, as
   84: this seems to have something to do with mount ordering.
   85: 
   86: ## mount order
   87: 
   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
   91: /etc/rc.local.
   92: 
   93: NetBSD current after 20200301 mounts ZFS first. \todo Explain
   94: consequences.
   95: 
   96: ## TRIM
   97: 
   98: There is some notion of TRIM and zfs using it.
   99: 
  100: \todo Explain how this relates to NetBSD.
  101: 
  102: # Memory usage
  103: 
  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 :-)
  108: 
  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.
  111: 
  112: \todo Give ballpark level for minimum sane RAM, and the amount which
  113: is cleanly enough.
  114: 
  115: FreeBSD has some documentation about memory use.  There is a notion of
  116: a minimum of 1G, and using 1G for 1T of storage, and more if
  117: deduplication is enabled.  FreeBSD considers all i386 systems to be
  118: low memory; this appears to be a clue.
  119: 
  120: \todo Explain if the FreeBSD sysctl list applies, or if not what we
  121: should do instead.
  122: 
  123:   - [FreeBSD low memory documentation](https://www.freebsd.org/doc/handbook/zfs-advanced.html)
  124: 
  125: # Interoperability with other systems
  126: 
  127: \todo Explain pool version and feature flags relationship to FreeBSD,
  128: Linux, OpenIndiana/Illumos/?, and ?
  129: 
  130: 

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