ANNOUNCE-2.6

Subject:  ANNOUNCE: mdadm 2.6 - A tool for managing Soft RAID under Linux

I am pleased to announce the availability of
   mdadm version 2.6

It is available at the usual places:
   http://www.cse.unsw.edu.au/~neilb/source/mdadm/
and
   countrycode=xx.
   http://www.${countrycode}kernel.org/pub/linux/utils/raid/mdadm/
and via git at
   git://neil.brown.name/mdadm
   http://neil.brown.name/git?p=mdadm

mdadm is a tool for creating, managing and monitoring
device arrays using the "md" driver in Linux, also
known as Software RAID arrays.

Release 2.6 adds assorted fixes and improvements and a new major mode.
"Incremental Assembly"  via -I or --incremental can be used to
assemble an array one device at a time.  The idea is that you get
udev to run  "mdadm -Iq devicename" on each new block device that it
finds.  Anything that is part of an array gets included in an array as
appropriate.
Two special notes:
 1/ This is very new code and is probably buggy.  It passes a few basic
    tests, and helped me find some kernel bugs, but it is still fresh
    and should not be considered 'stable'.  Please test and provide
    feedback.
 2/ There is a bug in the linux kernel that makes incremental assembly
    not possible in general (you cannot safely remove a drive from an array
    that has not yet been started. This is needed if an old device was
    detected first).  If mdadm detects a kernel which might have the
    bug, it rejects --incremental requests.
    The bug will hopefully be fixed in 2.6.20 and this mdadm release
    contains patches for 2.6.18, 2.6.18.6 and 2.6.19.  Apply the
    appropriate patch to test --incremental.

Changelog Entries:
    -   Fixed UUID printing in "--detail --brief" for version1 metadata.
    -   --update=resync did exactly the wrong thing for version1 metadata.
	It caused a resync to not happen, rather than to happen.
    -   Allow --assemble --force to mark a raid6 clean when it has two
	missing devices (which is needed else if won't assemble.
	Without this fix it would only assemble if one or zero
	missing devices.
    -   Support --update=devicesize for cases where the underlying device
	can change size.
    -   Default to --auto=yes so the array devices with 'standard' names
	get created automatically, as this is almost always what is wanted.
    -   Give useful message if raid4/5/6 cannot be started because it is
	not clean and is also degraded.
    -   Increase raid456 stripe cache size if needed to --grow the array.
	The setting used unfortunately requires intimate knowledge of the
	kernel, and it not reset when the reshape finishes.
    -   Change 'Device Size' to 'Used Dev Size' because it only shows how
	much of each device is actually used, not how big they are.
    -   --wait or -W will wait for resync activity to finish on the given
	devices.
    -   Fix some problems with --update=uuid and add a test.
    -   If two drives in a raid5 disappear at the same time, then "-Af"
        will add them both in rather than just one and forcing the array
	to 'clean'.  This is slightly safer in some cases.
    -   Check device is large enough before hot-add: this improves quality
	of error message.
    -   Don't hold md device open for so long in --monitor mode - map_dev
	can be slow and interferes with trying to stop the array.
    -   Support --uuid= with --create to choose your own UUID.
    -   New major more "--incremental" for incremental assemble of arrays,
	intended for use with udev.

Development of mdadm is sponsored by
 SUSE Labs, Novell Inc.

NeilBrown  21st December 2006
Blessed Christmas to all.