Subject: ANNOUNCE: mdadm 3.3 - A tools for managing md Soft RAID under Linux
I am pleased to announce the availability of
mdadm version 3.3
It is available at the usual places:
http://www.kernel.org/pub/linux/utils/raid/mdadm/
and via git at
git://github.com/neilbrown/mdadm
git://neil.brown.name/mdadm
http://git.neil.brown.name/git/mdadm
This is a major new release so don't be too surprised if there are a
few issues. If I hear about them they will be fixed in 3.3.1.
git log reports nearly 500 changes since 3.2.6 so I won't list them
all.
Some highlights are:
- Some array reshapes can proceed without needing backup file.
This is done by changing the 'data_offset' so we never need to write
any data back over where it was before. If there is no "head space"
or "tail space" to allow data_offset to change, the old mechanism
with a backup file can still be used.
- RAID10 arrays can be reshaped to change the number of devices,
change the chunk size, or change the layout between 'near'
and 'offset'.
This will always change data_offset, and will fail if there is no
room for data_offset to be moved.
- "--assemble --update=metadata" can convert a 0.90 array to a 1.0 array.
- bad-block-logs are supported (but not heavily tested yet)
- "--assemble --update=revert-reshape" can be used to undo a reshape
that has just been started but isn't really wanted. This is very
new and while it passes basic tests it cannot be guaranteed.
- improved locking between --incremental and --assemble
- uses systemd to run "mdmon" if systemd is configured to do that.
- kernel names of md devices can be non-numeric. e.g. "md_home" rather than
"md0". This will probably confuse lots of other tools, so you need to
echo CREATE names=yes >> /etc/mdadm.conf
or the feature will not be used. (you also need a reasonably new kernel).
- "--stop" can be given a kernel name instead of a device name. i.e
mdadm --stop md4
will work even if /dev/md4 doesn't exist.
- "--detail --export" has some information about the devices in the array
- --dump and --restore can be used to backup and restore the metadata on an
array.
- Hot-replace is supported with
mdadm /dev/mdX --replace /dev/foo
and
mdadm /dev/mdX --replace /dev/foo --with /dev/bar
- Config file can be a directory in which case all "*.conf" files are
read in lexical order.
Default is to read /etc/mdadm.conf and then /etc/mdadm.conf.d
Thus
echo CREATE name=yes > /etc/mdadm.conf.d/names.conf
will also enable the use of named md devices.
- Lots of improvements to DDF support including adding support for
RAID10 (thanks Martin Wilck).
and lots of bugfixes and other little changes.
NeilBrown 3rd September 2013
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