Bug#593658: default compression=on?
Brett Dikeman a écrit :
> On Thu, Aug 19, 2010 at 8:55 PM, Tuco <email@example.com> wrote:
>> I suggest enabling compression by default when creating new ZFS filesystems.
> I suggest giving the user the option during an install, if ZFS is
> supported in that phase. That has a definite benefit, as ZFS only
> compresses data that makes it to disk after compression is flipped on.
> Turning on compression after an install is, at least for things like
> /usr, largely pointless; eventually, as packages get updated etc, more
> and more of the filesystem will become compressed, but...
> Point worth noting: it's only of value if the data you have is by and
> large compressable! If you're a photographer and work with mostly RAW
> and JPEGs, compression is going to be a waste of CPU cycles and maybe
> (this is a wild guess) increase CPU cache misses?
> It'd probably be worth talking to the ZFS developers to find out why
> compression isn't enabled by default in Solaris/OpenSolaris. They
> probably had some logic behind it, and it might be relevant.
I agree that enabling it by default without understanding all the
benefits/drawback is not something that should be done. Especially if
the default is different that what user expect (it is not the default on
OpenSolaris/FreeBSD, btrfs compression is disabled by default).
The best would indeed be to provide a way to create ZFS partitions
during the installation. Currently this is not the case, and there is
some work to do here. It is probably not straightforward, as you first
need to create a pool, then a filesystem. It's probably comparable to an
LVM installation in some senses. If someone wants to start working on
partman-zfs, please note that the zfsutils-udeb is available, and that a
patch for parted has been posted on the parted-devel mailing-list.
Aurelien Jarno GPG: 1024D/F1BCDB73