Date: Tue, 18 Feb 2014 21:25:26 -0800 From: aurfalien <aurfalien@gmail.com> To: freebsd@fongaboo.com Cc: questions@freebsd.org Subject: Re: ZFS on Hardware RAID controller Message-ID: <77EB3C34-7CBF-460C-9173-F5CE3A96EAA6@gmail.com> In-Reply-To: <alpine.BSF.2.00.1402182250080.4903@helix.wtfayla.net> References: <alpine.BSF.2.00.1402111550250.5347@helix.wtfayla.net> <CAF6rxgku91Rz037H-rpBCzc9G5bu5=KOiAm1Wms3%2B1Xcz%2BJjtQ@mail.gmail.com> <alpine.BSF.2.00.1402181717580.4903@helix.wtfayla.net> <CAF6rxgkVWm9AbM8SWCA3oHg8DHwSrRbSTW%2Ba%2BE9o%2Bky9SKNc2w@mail.gmail.com> <alpine.BSF.2.00.1402182250080.4903@helix.wtfayla.net>
next in thread | previous in thread | raw e-mail | index | archive | help
Well, I think the best thing is to config a ZFS server for yourself. Its one thing to read about it, but another to do it and you would most = certainly be in a better position to sell ZFS once you know how it works = through practice. The web is rich with ZFS info. I=92m speaking for personal experience. - aurf "Janitorial Services" On Feb 18, 2014, at 7:58 PM, freebsd@fongaboo.com wrote: >=20 > I was speaking to someone else about this today, and it eventually = became apparent that we were getting into a sort-of = Abbott-and-Costello-Who's-on-First confusion... because apparently = people can mean different things when they use the term 'JBOD'. >=20 > What I have always meant when I say 'JBOD' is a (not really) RAID mode = that simply concatenates the drives into one volume in a serial fashion, = ie. 'spanning'. Most RAID controllers and RAID-enabled NAS units that I = have interacted with in my life have offered this mode and referred to = it as 'JBOD'. >=20 > In this kind of mode, the motherboard and the OS still thinks it sees = only a single volume. So now I am gathering that this is also not ideal = for ZFS, since it would still not be aware of multiple physical volumes = and be unable to optimize accordingly. >=20 > I'm learning for the first time that sometimes 'JBOD' can also refer = to each individual drive being mounted separately at least as far as the = controller and the motherboard is concerned. >=20 > I just want to confirm 100% that this is how you are recommending = multiple drives be configured for ZFS. Because when I started the thread = I was thinking of JBOD as 'spanning'. >=20 >=20 > FONG >=20 >=20 >=20 > On Tue, 18 Feb 2014, Eitan Adler wrote: >=20 >> On Tue, Feb 18, 2014 at 5:27 PM, <freebsd@fongaboo.com> wrote: >>>=20 >>> When we spoke, you noted that when installing ZFS on multiple disks >>> connected to a hardware RAID controller, it is best to config it to = JBOD. >>=20 >> There are a few reasons for this. >> (a) Hardware RAID serves as a single point of failure: if the >> contoller dies you have neither disk >> (b) As Andrew noted , using hardware RAID means that ZFS won't be = able >> to tell which disk is which. The ZFS management tools won't work as >> expected (they will show only one disk). >> (c) Since ZFS implements RAID itself it can use knowledge about the >> physical disks for better performance >>=20 >> Also see: https://en.wikipedia.org/wiki/ZFS#ZFS_and_hardware_RAID >>=20 >>> I tried to explain this to a colleague, but they were skeptical. = Would you >>> (or anyone) be willing to give me a one or two line sales-pitch on >>=20 >> "ZFS does RAID better than the controller." >>=20 >>> why one >>> should abandon traditional notions of RAID performance in favor of = allowing >>> ZFS to do disk management? >>=20 >> The goal isn't to give up on RAID but move its implementation to ZFS. >>=20 >> --=20 >> Eitan Adler >> Source, Ports, Doc committer >> Bugmeister, Ports Security teams >> _______________________________________________ >> freebsd-questions@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-questions >> To unsubscribe, send any mail to = "freebsd-questions-unsubscribe@freebsd.org" >>=20 > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to = "freebsd-questions-unsubscribe@freebsd.org"
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?77EB3C34-7CBF-460C-9173-F5CE3A96EAA6>