Date: Wed, 26 Mar 2014 21:19:53 +0100 From: Andrea Venturoli <ml@netfence.it> To: freebsd-questions@freebsd.org Subject: Partition alignment Message-ID: <53333669.7000802@netfence.it>
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Hello. I'm looking for confirmation that the following partition alignement will *not* result in performance penalties: > root@:~ # mfiutil show volumes > mfi0 Volumes: > Id Size Level Stripe State Cache Name > mfid0 ( 835G) RAID-5 256k OPTIMAL Enabled > root@:~ # fdisk /dev/mfid0 > ******* Working on device /dev/mfid0 ******* > parameters extracted from in-core disklabel are: > cylinders=109053 heads=255 sectors/track=63 (16065 blks/cyl) > > Figures below won't work with BIOS for partitions not in cyl 1 > parameters to be used for BIOS calculations are: > cylinders=109053 heads=255 sectors/track=63 (16065 blks/cyl) > > Media sector size is 512 > Warning: BIOS sector numbering starts with sector 1 > Information from DOS bootblock is: > The data for partition 1 is: > sysid 165 (0xa5),(FreeBSD/NetBSD/386BSD) > start 63, size 1751936382 (855437 Meg), flag 80 (active) > beg: cyl 0/ head 1/ sector 1; > end: cyl 1023/ head 254/ sector 63 > The data for partition 2 is: > <UNUSED> > The data for partition 3 is: > <UNUSED> > The data for partition 4 is: > <UNUSED> > root@:~ # bsdlabel /dev/mfid0s1 > # /dev/mfid0s1: > 8 partitions: > # size offset fstype [fsize bsize bps/cpg] > a: 33554432 1224736768 4.2BSD 0 0 0 > b: 33554432 16777216 swap > c: 1751936382 0 unused 0 0 # "raw" part, don't edit > d: 16777216 0 4.2BSD 0 0 0 > e: 67108864 50331648 4.2BSD 0 0 0 > f: 33554432 117440512 4.2BSD 0 0 0 > g: 536870912 150994944 4.2BSD 0 0 0 > h: 536870912 687865856 4.2BSD 0 0 0 Or, again: > root@:~ # gpart show /dev/mfid0 > => 63 1751949249 mfid0 MBR (835G) > 63 1751936382 1 freebsd [active] (835G) > 1751936445 12867 - free - (6.3M) > root@:~ # gpart show /dev/mfid0s1 > => 0 1751936382 mfid0s1 BSD (835G) > 0 16777216 4 freebsd-ufs (8.0G) > 16777216 33554432 2 freebsd-swap (16G) > 50331648 67108864 5 freebsd-ufs (32G) > 117440512 33554432 6 freebsd-ufs (16G) > 150994944 536870912 7 freebsd-ufs (256G) > 687865856 536870912 8 freebsd-ufs (256G) > 1224736768 33554432 1 freebsd-ufs (16G) > 1258291200 493645182 - free - (235G) AFAICT the partition are correctly aligned within the slice, but I'm not sure about the slice itself. Thanks to anyone who will help. bye av.home | help
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