November 13, 2009

Introducing ZFS support in portshaker(8)

Categories: FreeBSD, Sysadmin.

portshaker(8) is a tool designed for merging partial ports trees into the FreeBSD ports tree. In other words, it implements some kind of overlay for the FreeBSD ports.

When merging port trees, portshaker(8) first clones the upstream FreeBSD ports tree to the target location. For this purpose, portshaker(8) used to rely on rsync(1) because the target ports tree was supposed to be quite near to the source ports tree. With an UFS file-system, it took my computer circa 10 minutes to merge the 390 Mib of files.

I recently switched to full ZFS, and this gave the clone process a boost: less than four minutes where required to perform the clone action for the first time, and thanks to caching, a single minute was enought to clone a second time.

But ZFS provides cloning capabilities, thus, I added support for the ZFS file-system into portshaker(8). Enabling this feature is as simple as adding the following to /usr/local/etc/portshaker.conf:


There is however a prerequisite for this to work: the target ports tree's parent directory and the source directory have to be ZFS filesystems. For example, on my computer, the FreeBSD upstream ports are stored in /var/cache/portshaker/freebsd and I merge my ports to the usual /usr/ports directory. All these directories are ZFS filesystems:

romain@marvin ~ % zfs list /usr/ports /var/cache/portshaker /var/cache/portshaker/freebsd
NAME                                USED  AVAIL  REFER  MOUNTPOINT
data/usr/ports                     57,1M  80,9G   402M  /usr/ports
data/var/cache/portshaker           514M  80,9G  48,6M  /var/cache/portshaker
data/var/cache/portshaker/freebsd   427M  80,9G   390M  /var/cache/portshaker/freebsd

When merging, portshaker(8) snapshots the FreeBSD ports and clone them to the target ports tree. This requires only a few seconds to achieve.

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On November 16, 2009, rhaamo wrote:

cool \o/

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