Date: Mon, 02 Dec 2013 12:35:03 -0500 From: "Mike." <the.lists@mgm51.com> To: freebsd-questions@freebsd.org Subject: Re: gmirror, gpart and MBR vs GPT in the Handbook Message-ID: <201312021235030914.007AF1DF@smtp.24cl.home> In-Reply-To: <20131202182623.43331984.freebsd@edvax.de> References: <201311301303210813.05DE187E@smtp.24cl.home> <alpine.BSF.2.00.1311301352140.99113@wonkity.com> <201312011121580096.005D00FB@smtp.24cl.home> <alpine.BSF.2.00.1312011016490.5791@wonkity.com> <201312021213320528.00673D5F@smtp.24cl.home> <20131202182623.43331984.freebsd@edvax.de>
next in thread | previous in thread | raw e-mail | index | archive | help
On 12/2/2013 at 6:26 PM Polytropon wrote: |On Mon, 02 Dec 2013 12:13:32 -0500, Mike. wrote: |> My understanding is that MBR can be used with drives only up to |> and including 2TB in size. So if I use MBR, the maximum drive |> size I could use would be 2TB. Is that correct? | |Don't confuse partitioning schemes and file systems. Both are |different things, happening on different "layers". To make it |simpler than it probably is: | |Partitioning = | a) MBR with classic tools (fdisk, bsdlabel) | b) MBR with modern tool (gpart) | c) GPT (gpart) | d) Dedicated (only the "bsdlabel part") | |RAID concepts = | a) mirror | b) stripe | c) combined and extended forms ... | |File system = | a) UFS | option +U: soft updates | option +J: journal | b) ZFS | |Of course ZFS can handle things like "RAID concepts" already |internally, whereas UFS would use gstripe and gmirror as |"little helpers" - it will run on top of them, i. e., you |initialize the device that represents the whole mirror |instead of individually dealing with the drives that the |mirror is constructed of. | |Regarding UFS's 2 TB limitation: | |http://www.freebsd.org/projects/bigdisk/ | |Additionally, MBR can be troublesome on bigger hard disks |or stripes. | |http://www.freebsd.org/doc/handbook/bsdinstall-partitioning.html | |Today's consensus seems to be: | |If you use ZFS, let ZFS deal with everything. | |If you use UFS, use gpart for preparation work. Use GPT when |possible, MBR only in exceptions, and dedicated if and only |if you really _really_ know what you're doing. :-) ============= Following the bsdinstall-partitioning link you cited, and then following a link on that page, I wind up here: http://en.wikipedia.org/wiki/Master_boot_record which states: "...The organization of the partition table in the MBR limits the maximum addressable storage space of a disk to 2 TB ...." That (and other places) is where I got the 2TB limit of MBR into my head. Am I misunderstanding that statement? Thanks.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201312021235030914.007AF1DF>