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(asterisk.enaza.ru [91.237.76.254]) by elf.hq.norma.perm.ru (8.15.2/8.15.2) with ESMTPS id w347LpMD024425 (version=TLSv1.2 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO) for ; Wed, 4 Apr 2018 12:21:51 +0500 (YEKT) (envelope-from eugene@zhegan.in) To: freebsd-stable@FreeBSD.org From: "Eugene M. Zheganin" Subject: another question about zfs compression numbers Message-ID: <52b1c557-bdb5-3b9f-1ce1-32f698ae982c@zhegan.in> Date: Wed, 4 Apr 2018 12:21:51 +0500 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 Content-Type: text/plain; charset=koi8-r; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Spamd-Result: default: False [-998.10 / 25.00] WHITELISTED_IPS(-999.00)[91.237.76.254] AUTH_NA(1.00)[] RCVD_COUNT_TWO(0.00)[2] MID_RHS_MATCH_FROM(0.00)[] DMARC_NA(0.00)[zhegan.in] FROM_EQ_ENVFROM(0.00)[] ARC_NA(0.00)[] ASN(0.00)[asn:57973, ipnet:91.237.76.0/24, country:RU] FROM_HAS_DN(0.00)[] R_SPF_NA(0.00)[] TO_MATCH_ENVRCPT_ALL(0.00)[] TO_DN_NONE(0.00)[] MIME_GOOD(-0.10)[text/plain] RCPT_COUNT_ONE(0.00)[1] RCVD_TLS_ALL(0.00)[] R_DKIM_NA(0.00)[] IP_SCORE(0.00)[ip: (-9.88), ipnet: 91.237.76.0/24(-7.81), asn: 57973(-4.88), country: RU(0.12)] X-Rspamd-Server: localhost X-Rspamd-Scan-Time: 2.73 X-Rspamd-Queue-ID: w347LpMD024425 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 04 Apr 2018 07:22:01 -0000 Hello, I'm just trying to understand these numbers: 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: # du -h 18G . # ls -lh total 19316318 -rw-r----- 1 root wheel 232G 4 апр. 11:29 mp_userCoordsHistory.ibd # zfs get all data/test NAME PROPERTY VALUE SOURCE data/test type filesystem - data/test creation ср апр. 4 10:31 2018 - data/test used 18,4G - data/test available 9,95T - data/test referenced 18,4G - data/test compressratio 1.86x - data/test mounted yes - data/test quota none default data/test reservation none default data/test recordsize 128K default data/test mountpoint /data/test default data/test sharenfs off default data/test checksum on default data/test compression lz4 local data/test atime on default data/test devices on default data/test exec on default data/test setuid on default data/test readonly off default data/test jailed off default data/test snapdir hidden default data/test aclmode discard default data/test aclinherit restricted default data/test canmount on default data/test xattr off temporary data/test copies 1 default data/test version 5 - data/test utf8only off - data/test normalization none - data/test casesensitivity sensitive - data/test vscan off default data/test nbmand off default data/test sharesmb off default data/test refquota none default data/test refreservation none default data/test primarycache all default data/test secondarycache all default data/test usedbysnapshots 0 - data/test usedbydataset 18,4G - data/test usedbychildren 0 - data/test usedbyrefreservation 0 - data/test logbias latency default data/test dedup on inherited from data data/test mlslabel - data/test sync standard default data/test refcompressratio 1.86x - data/test written 18,4G - data/test logicalused 34,2G - data/test logicalreferenced 34,2G - data/test volmode default default data/test filesystem_limit none default data/test snapshot_limit none default data/test filesystem_count none default data/test snapshot_count none default data/test redundant_metadata all default # zpool status pool: data state: ONLINE scan: scrub repaired 0 in 28h24m with 0 errors on Thu Feb 15 13:26:36 2018 config: NAME STATE READ WRITE CKSUM data ONLINE 0 0 0 raidz1-0 ONLINE 0 0 0 da2 ONLINE 0 0 0 da3 ONLINE 0 0 0 da4 ONLINE 0 0 0 da5 ONLINE 0 0 0 da6 ONLINE 0 0 0 raidz1-1 ONLINE 0 0 0 da7 ONLINE 0 0 0 da8 ONLINE 0 0 0 da9 ONLINE 0 0 0 da10 ONLINE 0 0 0 da11 ONLINE 0 0 0 raidz1-2 ONLINE 0 0 0 da12 ONLINE 0 0 0 da13 ONLINE 0 0 0 da14 ONLINE 0 0 0 da15 ONLINE 0 0 0 da16 ONLINE 0 0 0