On 2010-01-28 at 00:30 +0100 Ragnar Sundblad sent off: > > Are there any plans to add unwritten extent support into ZFS or any reason > > why > > not? > > I have no idea, but just out of curiosity - when do you want that?
when you have many data streams being simultaneous written to disk over a long time you end up with highly fragmented files. When you write to a file with random seeks (think of torrent) you end up with an extremely fragmented file. When you have a virtual disk image which "grows" over time, you will get a fragmented disk image which affects performance bad. When you write to a file and you want to be sure you have enough space to write all the data, even if writing to that file takes some time, preallocation takes care the space is yours. Threre are plenty of reasons to do preallocation. With unwritten extent support preallocation is a cheap thing to do. Björn _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
