Date: Wed, 7 Oct 2015 22:48:08 -0453.75 From: "William A. Mahaffey III" <wam@hiwaay.net> Cc: FreeBSD Questions !!!! <freebsd-questions@freebsd.org> Subject: Re: The saga continues Message-ID: <5615E62E.6070908@hiwaay.net> In-Reply-To: <alpine.BSF.2.20.1510072118430.74151@wonkity.com> References: <5613CA68.6090909@hiwaay.net> <20151006212741.0e128a23.freebsd@edvax.de> <5614278F.10400@hiwaay.net> <alpine.BSF.2.20.1510062239530.9728@wonkity.com> <56159C14.2070207@hiwaay.net> <alpine.BSF.2.20.1510071814490.74151@wonkity.com> <5615DA5C.6010806@hiwaay.net> <alpine.BSF.2.20.1510072118430.74151@wonkity.com>
next in thread | previous in thread | raw e-mail | index | archive | help
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.
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?5615E62E.6070908>