by prefetched than helped. On i386 systems and systems with less than 4GB,
prefetch is now disabled by default. I've added a prefetch enable tunable, to
enable prefetching for those systems. The prefetch disable tunable will continue
to unconditionally disable prefetching.
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
o Fix linewrap issues.
o Fix two typos (s/Recomended/Recommended/ and s/tunning/tuning/)
o Remove a couple of extra instances of the word "of".
o Update names of kmem_size variables.
Approved by: pjd
than 2GB of RAM. This was because our physmem is long and 'physmem*PAGESIZE'
can be negative for more than 2GB of memory.
Reported by: Andrey V. Elsukov <bu7cher@yandex.ru>
It is not yet tested by Andrey, so there can be other problems, but this
was definiately a bug, so I'm committing a fix now.
- Allow to shrink ARC down to 16MB (instead of 64MB).
- Set arc_max to 1/2 of kmem_map by default.
- Start freeing things earlier when low memory situation is detected.
- Serialize execution of arc_lowmem().
I decided to setup minimum ZFS memory requirements to 512MB of RAM and 256MB of
kmem_map size. If there is less RAM or kmem_map, a warning will be printed.
World is cruel, be no better. In other words: modern file system requires
modern hardware:)
From ZFS administration guide:
"Currently the minimum amount of memory recommended to install a Solaris
system is 512 Mbytes. However, for good ZFS performance, at least one
Gbyte or more of memory is recommended."
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/)
