doing a UFS install and not the default HAMMER install. We also recommend installing from the CD ISO
and not the DVD ISO. The DVD ISO HAMMER install has bugs (see [[Known Release Issues|issues24]]).
+**Binary packages issue** - Due to bugs in 2009Q4 we had to use pkgsrc-current for the x86_64 img/iso
+and both gui images. The i386 img/iso uses 2009Q4. The binary packages on avalon are thus a bit
+out of date for the x86_64 and gui images.
+
+**disklabel64 issue** - The installer may fail to install a 64-bit disklabel due to a snooping
+bug in the kernel if a 32-bit disklabel was previously present on the drive. If you get this
+failure you can re-run fdisk -IB <drive> from a shell and then retry.
+
## DragonFly 2.6.1 Release Notes
### Release Improvements
* Updated opencrypto from FreeBSD-current
* Updated ACPI from FreeBSD 7.2
* Updated CPU initialization code From FreeBSD
+* Serious reduction in KVM use for i386
+* KVM expanded to 8GB for x86_64
+* Major performance fixes for random I/O
> ### HAMMER changes
* Updated to HAMMER version 4
* REDO generation and recovery added to support fast fsync
* Extended 'hammer snapls' output to print mountpoints and snapshot notes.
* 'hammer viconfig' takes editor preference into account now
-*
+* Numerous low-memory deadlocks fixed
> ### Hardware changes (non-networking)
* uchcom(4): The driver for WinChipHead CH341/CH340 is now working stable
> ### amd64 related changes
* amd64 has been renamed to x86_64
+* 64-bit vkernels now work on 64-bit boxes
> ### Removals
* The T/TCP extension is no longer supported
>### Security related
* ssh server: change defaults for new installations to disallow plain text passwords and allow root login via public key
->### General Improvements
+>### Big-ticket items
+
+**swapcache** - This is a mechanism which allows an attached solid state drive to be used to cache
+data and/or meta-data for other filesystems. The meta-data caching feature is particularly useful for
+machines which manage millions of files. About 2 million inodes and their related blockmaps can be
+cached per 1GB of SSD. DragonFly supports up to 32GB of swap per swap device (up to four) on i386
+and up to 512GB of swap per swap device on 64-bit, so a very large number of inodes can be cached.
+Please see the [swapcache(8)](http://leaf.dragonflybsd.org/cgi/web-man?command=swapcache§ion=ANY)
+manual page for more information.
+
+**HAMMER** - Our filesystem now supports a REDO log on top of the UNDO log it already had.
+The filesystem will use the REDO log forward-log write and file-extend operations which
+allows fsync to accomplish its goals with only REDO log writes. This greatly improves
+the speed of fsync without weakening HAMMER's fast-recovery feature.
+
+**tmpfs** - The tmpfs port we did from NetBSD is able to fully utilize the VM page
+cache on the system as well as swap space, with no duplication of data (unlike MFS)
+and very good cache characteristics which reduce or eliminate disk activity under
+nominal operation.