RUNBOOK ep0: PBS 4.2.2-1 -> 4.2.5-1, slope unchanged as predicted (R-341)

Both STOPs cleared by the operator. No code changed; documentation only.

STEP 3 (the run's primary deliverable): the full changelog range 4.2.2-1 ->
4.2.5-1 was read (128 lines, all three entries) and swept for
connection-handling vocabulary. Exactly one keyword hit, a false positive
("S3 ... honor the node's proxy settings" = HTTP proxy config for S3, not the
PBS proxy daemon). 4.2.5-1 is a manifest-hardening security release; 4.2.4-1
is S3 rate limits and a locking cache; 4.2.3-1 is UI/LDAP/tape. NOTHING
addresses descriptor lifetime or connection reaping. Recommendation was: do
not upgrade for this reason.

STOP 1: operator ruled to upgrade anyway for rehearsal value. Recorded as a
practice run, not a fix -- and the interpretation was fixed IN WRITING BEFORE
any numbers existed (stop1-ruling.txt): unchanged = expected; changed =
surprise. Neither outcome could then be rationalised into a success.

STOP 2: Hetzner snapshot 421440873, Available. Documented that it covers
/dev/sda ONLY -- /mnt/pbs-datastore is a separate Volume and is NOT in it, so
it is a software rollback and not a backup of the backup data.

UPGRADE: simulated first (0 to remove), then installed 09:51:00->09:51:06Z,
exit 0. Verified: 4.2.5-1 installed, both daemons active, effective open
files still 65536 (the drop-in survived the new package), Recv-Q 0, loopback
200, 200 from BOTH boxes over the tunnel with felhom-pbs active, and the hub
gauge refreshed post-upgrade at 11:59:31.

SLOPE: before +4 fd/1885 s = 183/day; after +5 fd/1919 s = 225/day. NOT
distinguishable -- one descriptor apart, Poisson +/-2 on such counts. The
higher after-figure is noise, not a regression and not an improvement. 30
minutes cannot settle it; R-341 files the +24 h and +7 d checks.

CORRECTIONS to this morning's own report, both published rather than quietly
fixed:
  - the "~85/day, ~2 years of runway" figures were WRONG. They came from a
    single 17-minute window with a delta of ONE descriptor. Real rate is
    183-200/day over two independent windows; runway ~357 days, not 2 years.
  - the leak was attributed to CLOSE-WAIT. It is mostly ESTAB: CLOSE-WAIT held
    flat at 1 while ESTAB grew 45->49, and at the wedge it was 1011 ESTAB vs
    543 CLOSE-WAIT. R-336's fix must target unreaped connections.
  - "proxmox-backup-api" reported inactive during verification; that unit does
    not exist. Bad query, not a fault, written down because it looked like one.

R-336 stays open: even a fixed leak would not make ~85k requests/day to a
weekly-write DR endpoint correct.

golden-currency still convicts (inherited R-334, controller 0.216.0 vs golden
0.214.0, untouched by this run), so this push is --no-verify per
.claude/rules/gates.md.

documentation/audits/evidence-ep0-pbs-upgrade-2026-08-18/step4b-upgrade.txt

@@ -0,0 +1,58 @@
+### UPGRADE START
+2026-08-18T09:51:00+00:00
+Reading package lists...
+Building dependency tree...
+Reading state information...
+The following additional packages will be installed:
+  proxmox-backup-client proxmox-backup-docs proxmox-enterprise-support-keyring
+The following NEW packages will be installed:
+  proxmox-enterprise-support-keyring
+The following packages will be upgraded:
+  proxmox-backup-client proxmox-backup-docs proxmox-backup-server
+3 upgraded, 1 newly installed, 0 to remove and 8 not upgraded.
+Need to get 47.8 MB of archives.
+After this operation, 1404 kB of additional disk space will be used.
+Get:1 http://download.proxmox.com/debian/pbs trixie/pbs-no-subscription amd64 proxmox-backup-client amd64 4.2.5-1 [3447 kB]
+Get:2 http://download.proxmox.com/debian/pbs trixie/pbs-no-subscription amd64 proxmox-backup-docs all 4.2.5-1 [6351 kB]
+Get:3 http://download.proxmox.com/debian/pbs trixie/pbs-no-subscription amd64 proxmox-enterprise-support-keyring all 1.1 [2988 B]
+Get:4 http://download.proxmox.com/debian/pbs trixie/pbs-no-subscription amd64 proxmox-backup-server amd64 4.2.5-1 [38.0 MB]
+perl: warning: Setting locale failed.
+perl: warning: Please check that your locale settings:
+	LANGUAGE = (unset),
+	LC_ALL = (unset),
+	LC_CTYPE = "UTF-8",
+	LC_NUMERIC = (unset),
+	LC_COLLATE = (unset),
+	LC_TIME = (unset),
+	LC_MESSAGES = (unset),
+	LC_MONETARY = (unset),
+	LC_ADDRESS = (unset),
+	LC_IDENTIFICATION = (unset),
+	LC_MEASUREMENT = (unset),
+	LC_PAPER = (unset),
+	LC_TELEPHONE = (unset),
+	LC_NAME = (unset),
+	LANG = "en_US.UTF-8"
+    are supported and installed on your system.
+perl: warning: Falling back to a fallback locale ("en_US.UTF-8").
+locale: Cannot set LC_CTYPE to default locale: No such file or directory
+locale: Cannot set LC_ALL to default locale: No such file or directory
+Fetched 47.8 MB in 1s (39.3 MB/s)
+(Reading database ... 
+(Reading database ... 5%
+(Reading database ... 10%
+(Reading database ... 15%
+(Reading database ... 20%
+(Reading database ... 25%
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+(Reading database ... 40%
+(Reading database ... 45%
+(Reading database ... 50%
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+(Reading database ... 65%
+(Reading database ... 70%
+(Reading database ... 75%
+(Reading database ... 80%
+(Reading database ... 85%