Date: Wed, 21 Jul 2010 22:39:26 -0500 From: Adam Vande More <amvandemore@gmail.com> To: Dan Langille <dan@langille.org> Cc: freebsd-stable <freebsd-stable@freebsd.org> Subject: Re: Using GTP and glabel for ZFS arrays Message-ID: <AANLkTikwNEXpTz-hpKLta0T3Lx67nRHtOaVLp_c7C8BI@mail.gmail.com> In-Reply-To: <AANLkTimbYGpC0aYGnE61J5ZopQVD9m8hrz07CZAnsvsq@mail.gmail.com> References: <4C47B57F.5020309@langille.org> <AANLkTimbYGpC0aYGnE61J5ZopQVD9m8hrz07CZAnsvsq@mail.gmail.com>
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On Wed, Jul 21, 2010 at 10:34 PM, Adam Vande More <amvandemore@gmail.com>wrote: > > > On Wed, Jul 21, 2010 at 10:05 PM, Dan Langille <dan@langille.org> wrote: > >> Why '-b 34'? Randi pointed me to >> http://en.wikipedia.org/wiki/GUID_Partition_Table where it explains what >> the first 33 LBA are used for. It's not for us to use here. >> >> Where SOMEVALUE is the number of blocks to use. I plan not to use all the >> available blocks but leave a few hundred MB free at the end. That'll allow >> for the variance in HDD size. >> >> Any suggestions/comments? Is there any advantage to using the -l option >> on 'gpart add' instead of the glabel above? >> > > You'll want to make sure your partitions are aligned, discussion here(says > 4k drives, but info pertinent to all): > > http://lists.freebsd.org/pipermail/freebsd-hackers/2010-March/031154.html > > My understanding is that you weren't booting from zfs, just using it as an > data file system. In that case, you'd want to use "gpart add -b 512 ..." > or some other multiple of 16. Even 1024 would be a good safe number. Also > GPT creates partitions not slices. Your resulting partitions with be > labeled something like ad0p1, ad0p2, etc. > > Also if you have an applicable SATA controller, running the ahci module with give you more speed. Only change one thing a time though. Virtualbox makes a great testbed for this, you don't need to allocate the VM a lot of RAM just make sure it boots and such. -- Adam Vande More
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