Date: Tue, 26 Dec 2017 17:24:54 +0100 From: "O. Hartmann" <ohartmann@walstatt.org> To: FreeBSD CURRENT <freebsd-current@freebsd.org> Subject: ZFS: alignment/boundary for partition type freebsd-zfs Message-ID: <20171226172521.611a89b0@thor.intern.walstatt.dynvpn.de>
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[-- Attachment #1 --] Running recent CURRENT on most of our lab's boxes, I was in need to replace and restore a ZFS RAIDZ pool. Doing so, I was in need to partition the disks I was about to replace. Well, the drives in question are 4k block size drives with 512b emulation - as most of them today. I've created the only and sole partiton on each 4 TB drive via the command sequence gpart create -s GPT adaX gpart add -t freebsd-zfs -a 4k -l nameXX adaX After doing this on all drives I was about to replace, something drove me to check on the net and I found a lot of websites giving "advices", how to prepare large, modern drives for ZFS. I think the GNOP trick is not necessary any more, but many blogs recommend to perform gpart add -t freebsd-zfs -b 1m -a 4k -l nameXX adaX to put the partition boundary at the 1 Megabytes boundary. I didn't do that. My partitions all start now at block 40. My question is: will this have severe performance consequences or is that negligible? Since most of those websites I found via "zfs freebsd alignement" are from years ago, I'm a bit confused now an consideration performing all this days-taking resilvering process let me loose some more hair as the usual "fallout" ... Thanks in advance, Oliver -- O. Hartmann Ich widerspreche der Nutzung oder Übermittlung meiner Daten für Werbezwecke oder für die Markt- oder Meinungsforschung (§ 28 Abs. 4 BDSG). [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- iLUEARMKAB0WIQQZVZMzAtwC2T/86TrS528fyFhYlAUCWkJ38QAKCRDS528fyFhY lHkfAf0XiTMZQorYLpmQLb9cJUfMk5BOD+KG88vGNH4Wl69LnC+IcivLe61Q/rNs CXu+AWozrcq0obUnwp9ryQ4mtl8vAgCepXbfFpMo6YLz18ilrCXLh6Uc+a4p3t5f CzuigwBNDLC75vtMob44wAzYtIJkkkkwgwE1lnRX2rgxO25p22lW =cusG -----END PGP SIGNATURE-----help
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