Date: Sun, 27 Jan 2013 14:01:33 +0100 From: Adam Nowacki <nowakpl@platinum.linux.pl> To: fs@FreeBSD.org Subject: RAID-Z wasted space - asize roundups to nparity +1 Message-ID: <5105252D.6060502@platinum.linux.pl>
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I've just found something very weird in the ZFS code. sys/cddl/contrib/opensolaris/uts/common/fs/zfs/vdev_raidz.c:504 in HEAD Can someone explain the reason behind this line of code? What it does is align on-disk record size to a multiple of number of parity disks + 1 ... this really doesn't make any sense. So far as I can tell those extra sectors are just padding - completely unused. For the array I'm using this results in 4.8% of wasted disk space - 1.7TB. It's a 12x 3TB disk RAID-Z2.
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