[OpenIndiana-discuss] Updates in OI

[Dave Miner]

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