Date: Mon, 13 Oct 2014 14:19:03 -0500 From: "Matthew D. Fuller" <fullermd@over-yonder.net> To: freebsd-stable <freebsd-stable@freebsd.org> Cc: Steven Hartland <killing@multiplay.co.uk> Subject: Re: getting to 4K disk blocks in ZFS Message-ID: <20141013191903.GR2161@over-yonder.net> In-Reply-To: <543C1E7B.4090204@bluerosetech.com> References: <540FF3C4.6010305@ish.com.au> <54100258.2000505@freebsd.org> <5410F0B4.9040808@ish.com.au> <A0A549F7A4094F519A3660697AB4983F@multiplay.co.uk> <543C1E7B.4090204@bluerosetech.com>
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On Mon, Oct 13, 2014 at 11:48:27AM -0700 I heard the voice of Darren Pilgrim, and lo! it spake thus: > > If the default is 4k and (for the limited time they're still common) > you use true 512b disks, you can waste space. Sure, but how much > space? The median file in /usr/ports is 408 bytes. Over 90% of the files are under 2k, which means the wastage for them is over 100% (before counting what gain compression might get). A little offhand mathery says it's about 78% extra overhead on the whole. And that includes the almost hundred megs (over 22% of the total size of the FS) for the INDEX.db, plus the ~90 megs of the flat INDEX files (another 20%). If you pull those out, the overhead is 130%. (To be sure, relatively few people have ports trees eating most of their space, but still; it's pretty pathological. I for one did decide some years back to always force 4k on any new FSen to make future life simpler, accepting the bloat, but it's there.) -- Matthew Fuller (MF4839) | fullermd@over-yonder.net Systems/Network Administrator | http://www.over-yonder.net/~fullermd/ On the Internet, nobody can hear you scream.
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