From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?Q?Ragnar_Kj=F8rstad?= Subject: Re: Agressive selective pre-allocation Date: Sat, 14 Dec 2002 03:06:52 +0100 Message-ID: <20021214030652.H2727@vestdata.no> References: <20021210074600.J26400@vestdata.no> <3DF5F679.1000700@namesys.com> Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Return-path: list-help: list-unsubscribe: list-post: Errors-To: flx@namesys.com Content-Disposition: inline In-Reply-To: <3DF5F679.1000700@namesys.com>; from reiser@namesys.com on Tue, Dec 10, 2002 at 05:13:13PM +0300 List-Id: Content-Type: text/plain; charset="iso-8859-1" To: Hans Reiser Cc: reiserfs-list@namesys.com On Tue, Dec 10, 2002 at 05:13:13PM +0300, Hans Reiser wrote: > >An alternative would be the possibility to tell the fs about the > >properties of the files. Maybe an ioctl to notify the fs that for this > >particular file the fs should allocate X blocks at the time? That would > >ensure that the files only get limited fragmentation and performance > >stays optimal. > > Veritas did this, and then their architect regretted that nobody=20 > actually used that code and advised me not to do it. You may have an=20 > advantage with open source though in that you can modify the important=20 > user space programs to use it. I was more thinking along the lines of: find /var/log -type f | xargs ioctl REISERFS_SLOW_GROWING But I guess syslog or whatever is used would have to be modified for it to happen automaticly on new files. My guess is that syslog-maintainers would not take patches for features like this unless it was done in a more generic way that could potentially be used by other filesystems as well.=20 > We have some block preallocation code in V3 for files that are kept open = > while being written to. You can look at that code if you want. You can = > also write a plugin for v4 that does what you want. Are you talking about the allocate on flush code? I'll check that out; allthough at this point it is of course more interesting to write code for reiserfs4 than v3 - in particular if the new improved infrastructure makes it easier. > While I will not take someone off another task to work on this, I will=20 > be open to patches from others. As I wrote in my original mail I don't have time to really work on this now, but maybe later. --=20 Ragnar Kj=F8rstad