Date: Wed, 4 Apr 2018 09:35:30 +0200 From: "Patrick M. Hausen" <hausen@punkt.de> To: "Eugene M. Zheganin" <eugene@zhegan.in> Cc: freebsd-stable@freebsd.org Subject: Re: another question about zfs compression numbers Message-ID: <8A5C86CA-C959-4DFF-9168-DD94CF46AC91@punkt.de> In-Reply-To: <52b1c557-bdb5-3b9f-1ce1-32f698ae982c@zhegan.in> References: <52b1c557-bdb5-3b9f-1ce1-32f698ae982c@zhegan.in>
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Hi all, > Am 04.04.2018 um 09:21 schrieb Eugene M. Zheganin <eugene@zhegan.in>: > I'm just trying to understand these numbers: >=20 > file size is 232G, it's actual size on the lz4-compressed dataset is = 18G, so then why is the compressratio only 1.86x ? And why logicalused = is 34.2G ? On one hand, 34.2G exactlyfits to the 1.86x compresstaio, but = still I don't get it. dataset is on raidz, 3 spans across 5 disk vdevs, = with total of 15 disks if it matters: A sparse file, possibly? The ZFS numbers refer to blocks. "Skipping" = zeroes at the VFS layer is not taken into account as fas as I know. Seriously, how = should it? If I'm not mistaken, ZFS will never get to see these empty blocks. Patrick --=20 punkt.de GmbH Internet - Dienstleistungen - Beratung Kaiserallee 13a Tel.: 0721 9109-0 Fax: -100 76133 Karlsruhe info@punkt.de http://punkt.de AG Mannheim 108285 Gf: Juergen Egeling
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