[OpenIndiana-discuss] Updates in OI

[Judah Richardson]

On Tue, May 4, 2021 at 12:05 PM Lou Picciano <LouPicciano at comcast.net>
wrote:

>
>
> > On May 4, 2021, at 12:57 PM, Judah Richardson <judahrichardson at gmail.com>
> wrote:
> >
> > On Tue, May 4, 2021 at 8:51 AM Toomas Soome via openindiana-discuss <
> > openindiana-discuss at openindiana.org> wrote:
> >
> >>
> >>> On 4. May 2021, at 16:27, Dave Miner <dave.miner at oracle.com> wrote:
> >>>
> >>> 
> >>>
> >>> On 5/4/2021 8:59 AM, Yassine Chaouche wrote:
> >>>> Le 5/4/21 à 1:43 PM, Stephan Althaus a écrit :
> >>>>>
> >>>>> Hello!
> >>>>>
> >>>>> We have "Boot environments"
> >>>>>
> >>>>> On every "pkg update" you get a new BE that will be used on next
> >> reboot.
> >>>>
> >>>> This is just
> >>>>
> >>> ...
> >>>> Is this done by issuing a ZFS snapshot of the whole root partition ?
> or
> >>>> is it more granular ?
> >>>>
> >>>> If this is done via snapshots, this means writing to an evergrowing
> >> file
> >>>> on disk until the snapshot is removed. So the longer you keep a
> >> snapshot,
> >>>> the bigger the file gets.
> >>>>
> >>>
> >>> Yes, boot environments in the OpenSolaris-derived OS's are implemented
> >> using ZFS snapshots/clones of the root datasets.  Combined with IPS's
> >> optimizations to only update objects that have changed between package
> >> versions, you may find that boot environments for an update may not be
> >> nearly as large as the initial installation; it all depends on how much
> has
> >> changed.  Reclaiming space is as simple as deleting older boot
> environments
> >> when they're no longer needed.  It's not at all unusual for a system to
> >> have a dozen or more boot environments; some of the more masochistic
> among
> >> us used to have systems with 100 or more.
> >>>
> >>> Dave
> >>>
> >>
> >> With old grub, the number is limited to 50 - 60 becsuse of memory setup.
> >> With loader, I did demo with 600, but since loader is using sliding
> window,
> >> the number of BE’s is not limited there.
> >>
> > Is there ever a situation in which the disk can run out of space due to
> too
> > many BEs? And if so, how does one go about automatically pruning
> > old/unwanted BEs?
>
> I’m sure your root pool could eventually be strained to ‘max’ by installed
> BEs (though I imagine you’d be well-aware of this approaching limit as the
> new update(?) BE is being built.)
>
My experience with such things is they tend to happen sooner than expected,
especially with CoW filesystems. I've had Raspberry Pi OS choke because apt
cache had filled up the microSD card and I've also had a Btrfs pool become
unwriteable due to too many rsync snapshots and snapshot subvolumes. I'm
always concerned by space consuming things that increase without some
predefined bound ;)

>
> As to automation: I myself don’t automate deletions (of older BEs), but
> make it a matter of ‘good hygiene’ to clean up oldest ones, including their
> snapshots, when it’s clear these are BEs I’d never need to return to.
>
Fair. I prefer automation so that the process doesn't become subject to my
fallible memory or other human error.

>
> On that point, I’d say there have only been perhaps one or two instances -
> in 10+ years - in which I’ve really felt a need to revert to a BE, and only
> then to the most-recent one.
>
I've only ever reverted to a BE once before, on Project Trident back when
it was still based on FreeBSD, so I can relate.

>
> >>
> >> Rgds,
> >> Toomas
> >> _______________________________________________
> >> openindiana-discuss mailing list
> >> openindiana-discuss at openindiana.org
> >> https://openindiana.org/mailman/listinfo/openindiana-discuss
> >>
> > _______________________________________________
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> > openindiana-discuss at openindiana.org
> > https://openindiana.org/mailman/listinfo/openindiana-discuss
>
>
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