From owner-freebsd-questions@freebsd.org Thu Oct 8 03:42:41 2015 Return-Path: Delivered-To: freebsd-questions@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 71FFC9D0DD8 for ; Thu, 8 Oct 2015 03:42:41 +0000 (UTC) (envelope-from wam@hiwaay.net) Received: from fly.hiwaay.net (fly.hiwaay.net [216.180.54.1]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 4053A1AE for ; Thu, 8 Oct 2015 03:42:40 +0000 (UTC) (envelope-from wam@hiwaay.net) Received: from kabini1.local (dynamic-216-186-213-32.knology.net [216.186.213.32] (may be forged)) (authenticated bits=0) by fly.hiwaay.net (8.13.8/8.13.8/fly) with ESMTP id t983gc7R029449 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES128-SHA bits=128 verify=NO) for ; Wed, 7 Oct 2015 22:42:39 -0500 Subject: Re: The saga continues References: <5613CA68.6090909@hiwaay.net> <20151006212741.0e128a23.freebsd@edvax.de> <5614278F.10400@hiwaay.net> <56159C14.2070207@hiwaay.net> <5615DA5C.6010806@hiwaay.net> Cc: FreeBSD Questions !!!! From: "William A. Mahaffey III" Message-ID: <5615E62E.6070908@hiwaay.net> Date: Wed, 7 Oct 2015 22:48:08 -0453.75 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 08 Oct 2015 03:42:41 -0000 On 10/07/15 22:34, Warren Block wrote: > On Wed, 7 Oct 2015, William A. Mahaffey III wrote: > >> On 10/07/15 19:32, Warren Block wrote: >>> On Wed, 7 Oct 2015, William A. Mahaffey III wrote: >>> >>>>> Please read the warning at the top of that page. The Handbook >>>>> shows the right way of using gmirror(8). My page on it mirrors >>>>> GPT partitions, which is likely to be a problem if one of the >>>>> drives ever fails. If you absolutely have to use gmirror(8) with >>>>> GPT, use only one partition per drive. >>>>> >>>> >>>> >>>> Can I partition the drives using '-s MBR', then mirror some of the >>>> partitions & create '-s BSD' slices inside of those mirrors ? >>> >>> Ow, my brain. Why are you simultaneously creating safe data storage >>> along with ultra-unsafe data storage? What is the end goal? >>> >>> Multiple mirrors between drive partitions is potentially dangerous. >>> Consider that drives often die only a few days or hours apart. Now >>> think of a two-drive system with multiple mirrored partitions. One >>> drive has died. Put in a new drive, create the multiple partitions >>> on it, and add them to the mirrors. All of them start replicating >>> at the same time, putting a big load on the original still-working >>> drive. The drive that is the same age as the drive that failed... >> >> Creating the safe storage for the system so I could (hopefully) get >> it rebooted & reconstructed if 1 of the 2 HDD's croaks. If your >> scenario happens (both HDD's croak almost together, or the 2nd one >> croaks under the load of replicating), I'm fried anyway. That also >> argues against any mirroring at all, same thing happens if I mirror >> both drives as per the handbook. > > The difference is that multiple mirrored partitions that are > replicating at the same time put both drives under lots of head > contention. It will also make it take much, much longer. Agreed, naturally I hope to avoid that contingency :-). > >>>> Specifically, I would partition each drive into 4 primary >>>> partitions, /boot, swap, 1 partition to be mirrored & then sliced >>>> up as per the handbook, & 1 partition to be striped & then sliced >>>> up ? I would probably mirror /boot as well, if feasible. It seems >>>> this might comport w/ all of the restrictions & possible meta-data >>>> conflicts, but I am definitely out of my area, hence the questions. >>>> TIA & have a good one. >>> >>> /boot is a directory in /, the boot partition is just a place to >>> store bootcode. They are separate things. >> >> Agreed, bad nomenclature on my part .... it would be boot-partition, >> swap, mirrored-partition & striped partition. >> >>> >>> What is the function of the RAID0 here? Can it be replaced with >>> tmpfs or maybe an SSD? >> >> >> To maximize available space for storing movies, etc. I would be >> slicing it into 2 slices, for /usr/local & /home. All stuff here >> would be backed up elsewhere on the LAN and/or recreatable. I just >> want the largest possible pool of GiB's available. > > ZFS with a RAIDZ1 is a reasonable compromise. Three drives instead of > two, the space of two drives, any one drive can fail but the array > still works. > Only 2 SATA slots on the (mini-ITX) mbd, tight case, not much room for anything else, thus pretty much stuck w/ 2 HDD's, I think. -- William A. Mahaffey III ---------------------------------------------------------------------- "The M1 Garand is without doubt the finest implement of war ever devised by man." -- Gen. George S. Patton Jr.