From 2e1cd5772babf3235e12fb49161f53f3931b1740 Mon Sep 17 00:00:00 2001 From: Ralph Boehme Date: Fri, 17 Jul 2026 11:24:08 +0200 Subject: [PATCH] WHATSNEW: SMB3 Persistent Handles MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Signed-off-by: Ralph Boehme Reviewed-by: Anoop C S Autobuild-User(master): Ralph Böhme Autobuild-Date(master): Fri Jul 17 11:21:41 UTC 2026 on atb-devel-224 --- WHATSNEW.txt | 40 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 40 insertions(+) diff --git a/WHATSNEW.txt b/WHATSNEW.txt index f8b902efdc4..809730ffcb6 100644 --- a/WHATSNEW.txt +++ b/WHATSNEW.txt @@ -16,6 +16,46 @@ UPGRADING NEW FEATURES/CHANGES ==================== +SMB3 Persistent Handles (Experimental) +-------------------------------------- + +Samba now includes experimental support for SMB3 Persistent Handles, +a fundamental building block for Transparent Failover. + +Persistent Handles allow SMB clients to reconnect after a server +restart or outage while retaining valid file handles. Samba persists +all necessary handle state to durable on-disk storage so that open +files can be reconstructed when clients reconnect. This enables +applications that depend on uninterrupted file access, such as virtual +machine storage and clustered database workloads, to tolerate +temporary server failures without having to reopen files. + +Persistent Handles are advertised through the SMB3 protocol capability +SMB2_CAP_PERSISTENT_HANDLES. To make use of them on a share, both the +global "smb3 persistent handles" option and the per-share +"continuous availability" option must be enabled. + +Because Persistent Handles require Samba to maintain SMB state, they +are only available on shares configured for SMB-exclusive +access. Specifically, they require: + +kernel oplocks = no +kernel share modes = no +posix locking = no + +These settings disable interoperability with local POSIX file access +and NFS clients on the affected share. + +Administrators should be aware that Persistent Handles incur a +significant performance cost. File handle metadata is synchronously +persisted to durable storage for every open, update, lease, and close +operation, increasing latency compared to traditional SMB file +serving. For this reason, the feature is intended only for workloads +that require Continuous Availability semantics and is not recommended +for general-purpose file servers. + +This feature is currently considered experimental. + JSON Audit logging ------------------ -- 2.47.3