Date: Tue, 19 Oct 2010 12:49:15 +0100 From: Pete French <petefrench@ticketswitch.com> To: pjd@FreeBSD.org Cc: freebsd-fs@freebsd.org Subject: Re: Converting a non-HAST ZFS pool to a HAST pool Message-ID: <E1P8Agt-0001Ob-6I@dilbert.ticketswitch.com> In-Reply-To: <20101018222611.GC2375@garage.freebsd.pl>
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> Maybe I'm missing something, but how do you guys check this? Both > gmirror and glabel use only single sector for its metadata, so 1kB in > total. HAST metadata takes 4kB plus activemap size, which depends on > provider size. I checked it by disconnecting one half of the mirror - which is on a separate machine in my case remember - and then setting that machine up with hast. Created the hast device and did a 'diskinfo' on the resulting device. Compared that to a 'diskinfo' on the original provider. Here are the results, for the bare disk, the hast device, the mirrored device, and partition 'a' on the mirrored device. I wrote a disklabel there when it was UFSA, in case you were wondering. diskinfo /dev/da0s1 /dev/da0s1 512 68718411776 134215648 0 16384 16447 255 32 diskinfo /dev/hast/serp0 /dev/hast/serp0 512 68718403584 134215632 0 0 diskinfo /dev/mirror/mysql0 /dev/mirror/mysql0 512 68718410752 134215646 0 0 diskinfo /dev/mirror/mysql0a /dev/mirror/mysql0a 512 68718402560 134215630 0 8192 8354 255 63 So my current zpool uses /dev/mirror/mysql0a which is 68718402560 bytes, and when I move to hast I will be using /dev/hast/serp0 which is 68718403584 bytes - i.e. 1024 bytes larger. Note that if it wasn't for the BSD style disklabel it would be larger, and wouldnt work. -pete.
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