Few new things available from now on:
- Data deduplication.
- Triple parity RAIDZ (RAIDZ3).
- zfs diff.
- zpool split.
- Snapshot holds.
- zpool import -F. Allows to rewind corrupted pool to earlier
transaction group.
- Possibility to import pool in read-only mode.
MFC after: 1 month
The programmer was aware that alignment was not guaranteed in the
packed structure and used bzero() to NULL out the pointers.
However, on ia64, the compiler is quite agressive in finding ILP
and calls to bzero() are often replaced by simple assignments (i.e.
stores). Especially when the width or size in question corresponds
with a store instruction (i.e. st1, st2, st4 or st8).
The problem here is not a compiler bug. The address of the memory
to zero-out was given by '&packed->nvl_priv' and given the type of
the 'packed' pointer the compiler could assume proper alignment for
the replacement of bzero() with an 8-byte wide store to be valid.
The problem is with the programmer. The programmer knew that the
address did not have the alignment guarantees needed for a regular
assignment, but failed to inform the compiler of that fact. In
fact, the programmer told the compiler the opposite: alignment is
guaranteed.
The fix is to avoid using a pointer of type "nvlist_t *" and
instead use a "char *" pointer as the basis for calculating the
address. This tells the compiler that only 1-byte alignment can
be assumed and the compiler will either keep the bzero() call
or instead replace it with a sequence of byte-wise stores. Both
are valid.
Approved by: re (kib)
This bring huge amount of changes, I'll enumerate only user-visible changes:
- Delegated Administration
Allows regular users to perform ZFS operations, like file system
creation, snapshot creation, etc.
- L2ARC
Level 2 cache for ZFS - allows to use additional disks for cache.
Huge performance improvements mostly for random read of mostly
static content.
- slog
Allow to use additional disks for ZFS Intent Log to speed up
operations like fsync(2).
- vfs.zfs.super_owner
Allows regular users to perform privileged operations on files stored
on ZFS file systems owned by him. Very careful with this one.
- chflags(2)
Not all the flags are supported. This still needs work.
- ZFSBoot
Support to boot off of ZFS pool. Not finished, AFAIK.
Submitted by: dfr
- Snapshot properties
- New failure modes
Before if write requested failed, system paniced. Now one
can select from one of three failure modes:
- panic - panic on write error
- wait - wait for disk to reappear
- continue - serve read requests if possible, block write requests
- Refquota, refreservation properties
Just quota and reservation properties, but don't count space consumed
by children file systems, clones and snapshots.
- Sparse volumes
ZVOLs that don't reserve space in the pool.
- External attributes
Compatible with extattr(2).
- NFSv4-ACLs
Not sure about the status, might not be complete yet.
Submitted by: trasz
- Creation-time properties
- Regression tests for zpool(8) command.
Obtained from: OpenSolaris
ZFS file system was ported from OpenSolaris operating system. The code in under
CDDL license.
I'd like to thank all SUN developers that created this great piece of software.
Supported by: Wheel LTD (http://www.wheel.pl/)
Supported by: The FreeBSD Foundation (http://www.freebsdfoundation.org/)
Supported by: Sentex (http://www.sentex.net/)
