Date: Fri, 20 Sep 2019 08:29:08 -0700 From: Freddie Cash <fjwcash@gmail.com> To: Slawa Olhovchenkov <slw@zxy.spb.ru> Cc: Michael Gmelin <grembo@freebsd.org>, Kurt Jaeger <lists@opsec.eu>, Toomas Soome <tsoome@me.com>, FreeBSD-Current <freebsd-current@freebsd.org> Subject: Re: Lockdown adaX numbers to allow booting ? Message-ID: <CAOjFWZ6O4H9atcV-C-ZV0xye24P%2B69frgaVez98ZiGytzweOuw@mail.gmail.com> In-Reply-To: <20190920143531.GB38096@zxy.spb.ru> References: <20190919140219.GE2863@home.opsec.eu> <7E0AE025-596C-457E-BC40-41217857A3CD@me.com> <20190919155713.GG2863@home.opsec.eu> <3C855A39-BF79-4430-98CB-CB9174768E11@freebsd.org> <20190920143531.GB38096@zxy.spb.ru>
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On Fri, Sep 20, 2019 at 7:35 AM Slawa Olhovchenkov <slw@zxy.spb.ru> wrote: > On Thu, Sep 19, 2019 at 06:04:54PM +0200, Michael Gmelin wrote: > > What about gpart output of the pool drives? > > > > In general you would create zpools using gptids or gpt labels, not the > devices, so you=E2=80=99re independent of device numbering. The boot load= er should > only be installed on drives that contain the boot pool (maybe you have ol= d > boot loaders on data drives?). > > ZFS work w/ ZFS labels, not w/ device names/gptids/gpt labels. > You don't worry about changed device names aroud reboots. > Very true, from ZFS' point of view. It writes a ZFS label to whichever GEOM provider you hand it (file, iSCSI device, raw device, MBR partition, GPT partition, etc), and it will find it's pool members based on those labels. ZFS doesn't care where the device is physically connected in the system, just that it is connected. But the ZFS labels aren't what it will display in "zpool list -v" or "zpool status" output. That will show the GEOM provider you gave it (and, depending on the order that GEOM tastes the devices, and what's enabled/disabled in loader.conf, that output can change). That's where it's useful to have human-readable, descriptive labels (like GPT partition labels), and to disable all the GEOM ID systems you won't be using via loader.conf. So that when things go sideways, and a disk dies, you can find it quickly and easily. Much easier to replace "gpt/jbod3-a6" in a multi-chassis storage system with 100+ drives than to figure out which bay corresponds to "ada73" after a couple of reboots that may or may not have changed the PCI bus enumeration direction, or after replacing an HBA that enumerates drives a different way (da vs ada), or after a BIOS/EFI upgrade that renumbers things, or any other number of situations. (We've run into most of these, and have come to rely on GPT partition labels for just this reason; and we stick the drive serial number on the outside of the bay, just in case). It's not a ZFS requirement. It just makes things easier for the admin down the road. Especially if the admin team changes or inherits systems. :) --=20 Freddie Cash fjwcash@gmail.com
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