Date: Thu, 09 Apr 2015 16:39:00 -0500 From: Rick Romero <rick@havokmon.com> To: freebsd-fs <freebsd-fs@freebsd.org> Subject: ZFS 10.1 send single snapshot - space 'used' irregularity Message-ID: <20150409163900.Horde.ZLVwr91i2UaonmJT1bC-Pw1@www.vfemail.net>
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I have 3 servers, A, B, C. I'm building C to replace A, and replicating the data to C from backup B. A is offsite in relation to B and C. All servers are FreeBSD 10.1, except A - which is 9.2. I'm confused on disk usage. Not so much a GB here or there, but 250GB is 'unaccounted for' on C. C and A should be a pretty close match. A - looks correct sysvolssd2/home used 495G - sysvolssd2/home usedbysnapshots 37.9G - sysvolssd2/home usedbydataset 456G - sysvolssd2/home usedbychildren 669M - sysvolssd2/home usedbyrefreservation 0 - sysvolssd2/home logicalused 585G - NAME SIZE ALLOC FREE CAP DEDUP HEALTH ALTROOT sysvolssd2 1.39T 744G 680G 52% 1.00x ONLINE - B - looks correct (backup of A, holds more snapshots and other crap than A) sysvol/primessd_home used 777G - sysvol/primessd_home usedbysnapshots 240G - sysvol/primessd_home usedbydataset 537G - sysvol/primessd_home usedbychildren 0 - sysvol/primessd_home usedbyrefreservation 0 - sysvol/primessd_home logicalused 754G - NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT sysvol 4.53T 2.43T 2.10T 20% - 53% 1.00x ONLINE - C - missing what appears to be the multiple snapshot data. Only the latest snapshot was sent, not the entire dataset. So 531GB is close enough to the 537G of B's dataset. sysvol_enc/home used 758G - sysvol_enc/home usedbysnapshots 3.00M - sysvol_enc/home usedbydataset 752G - sysvol_enc/home usedbychildren 5.84G - sysvol_enc/home usedbyrefreservation 0 - sysvol_enc/home logicalused 531G - NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT sysvol_enc 1.39T 1.12T 277G 49% - 80% 1.00x ONLINE - C is geli encrypted and B is not. Unfortunately when I check another server that's geli encrypted, it looks fine: E - nlsysvol/home used 13.8G - nlsysvol/home usedbysnapshots 5.58G - nlsysvol/home usedbydataset 7.78G - nlsysvol/home usedbychildren 483M - nlsysvol/home usedbyrefreservation 0 - nlsysvol/home logicalused 12.0G - NAME SIZE ALLOC FREE FRAG EXPANDSZ CAP DEDUP HEALTH ALTROOT nlsysvol 115G 42.8G 72.2G - - 37% 1.00x ONLINE - So the difference shouldn't be related to the encryption. It's almost as if the send from B to C included all the incremental snapshots, but didn't actually account for them. Am I reading this wrong, or is something else not right ? Should I delete that dataset, re-send the entire original dataset, then delete the incremental snapshots? It makes me a little concerned that deleting a snapshot might delete the data which was written at that time, even though it was not deleted in followup snapshots... And I assume FRAG is fragmentation. 50% is a bit strange for a brand new receive, isn't it? help. :) Rick
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