bump version to 1.0.8-1

Signed-off-by: Thomas Lamprecht <t.lamprecht@proxmox.com>

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "proxmox-backup"
-version = "1.0.7"
+version = "1.0.8"
 authors = [
     "Dietmar Maurer <dietmar@proxmox.com>",
     "Dominik Csapak <d.csapak@proxmox.com>",

debian/changelog

@@ -1,3 +1,14 @@
+rust-proxmox-backup (1.0.8-1) unstable; urgency=medium
+
+  * Https Connector: use hostname instead of URL again to avoid certificate
+    verification issues.
+
+  * ui: task summary: add verification jobs to count
+
+  * docs: explain some technical details about datastores/chunks
+
+ -- Proxmox Support Team <support@proxmox.com>  Thu, 04 Feb 2021 12:39:49 +0100
+
 rust-proxmox-backup (1.0.7-1) unstable; urgency=medium
 
   * fix #3197: skip fingerprint check when restoring key

debian/copyright

@@ -1,4 +1,4 @@
-Copyright (C) 2019 Proxmox Server Solutions GmbH
+Copyright (C) 2019 - 2021 Proxmox Server Solutions GmbH
 
 This software is written by Proxmox Server Solutions GmbH <support@proxmox.com>
 

docs/conf.py

@@ -74,7 +74,7 @@ rst_epilog = epilog_file.read()
 
 # General information about the project.
 project = 'Proxmox Backup'
-copyright = '2019-2020, Proxmox Server Solutions GmbH'
+copyright = '2019-2021, Proxmox Server Solutions GmbH'
 author = 'Proxmox Support Team'
 
 # The version info for the project you're documenting, acts as replacement for

docs/index.rst

@@ -33,6 +33,7 @@ in the section entitled "GNU Free Documentation License".
    pve-integration.rst
    pxar-tool.rst
    sysadmin.rst
+   technical-overview.rst
    faq.rst
 
 .. raw:: latex

docs/introduction.rst

@@ -161,7 +161,7 @@ of the issue and will send a notification once it has been solved.
 License
 -------
 
-Copyright (C) 2019-2020 Proxmox Server Solutions GmbH
+Copyright (C) 2019-2021 Proxmox Server Solutions GmbH
 
 This software is written by Proxmox Server Solutions GmbH <support@proxmox.com>
 

docs/technical-overview.rst

@@ -0,0 +1,166 @@
+Technical Overview
+==================
+
+.. _technical_overview:
+
+Datastores
+----------
+
+A Datastore is the logical place where :ref:`Backup Snapshots
+<backup_snapshot>` and their chunks are stored. Snapshots consist of a
+manifest, blobs, dynamic- and fixed-indexes (see :ref:`terminology`), and are
+stored in the following directory structure:
+
+ <datastore-root>/<type>/<id>/<time>/
+
+The deduplication of datastores is based on reusing chunks, which are
+referenced by the indexes in a backup snapshot. This means that multiple
+indexes can reference the same chunks, reducing the amount of space needed to
+contain the data (even across backup snapshots).
+
+Chunks
+------
+
+A chunk is some (possibly encrypted) data with a CRC-32 checksum at the end and
+a type marker at the beginning. It is identified by the SHA-256 checksum of its
+content.
+
+To generate such chunks, backup data is split either into fixed-size or
+dynamically sized chunks. The same content will be hashed to the same checksum.
+
+The chunks of a datastore are found in
+
+ <datastore-root>/.chunks/
+
+This chunk directory is further subdivided by the first four byte of the chunks
+checksum, so the chunk with the checksum
+
+ a342e8151cbf439ce65f3df696b54c67a114982cc0aa751f2852c2f7acc19a8b
+
+lives in
+
+ <datastore-root>/.chunks/a342/
+
+This is done to reduce the number of files per directory, as having many files
+per directory can be bad for file system performance.
+
+These chunk directories ('0000'-'ffff') will be preallocated when a datastore
+is created.
+
+Fixed-sized Chunks
+^^^^^^^^^^^^^^^^^^
+
+For block based backups (like VMs), fixed-sized chunks are used. The content
+(disk image), is split into chunks of the same length (typically 4 MiB).
+
+This works very well for VM images, since the file system on the guest most
+often tries to allocate files in contiguous pieces, so new files get new
+blocks, and changing existing files changes only their own blocks.
+
+As an optimization, VMs in `Proxmox VE`_ can make use of 'dirty bitmaps', which
+can track the changed blocks of an image. Since these bitmap are also a
+representation of the image split into chunks, there is a direct relation
+between dirty blocks of the image and chunks which need to get uploaded, so
+only modified chunks of the disk have to be uploaded for a backup.
+
+Since the image is always split into chunks of the same size, unchanged blocks
+will result in identical checksums for those chunks, so such chunks do not need
+to be backed up again. This way storage snapshots are not needed to find the
+changed blocks.
+
+For consistency, `Proxmox VE`_ uses a QEMU internal snapshot mechanism, that
+does not rely on storage snapshots either.
+
+Dynamically sized Chunks
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+If one does not want to backup block-based systems but rather file-based
+systems, using fixed-sized chunks is not a good idea, since every time a file
+would change in size, the remaining data gets shifted around and this would
+result in many chunks changing, reducing the amount of deduplication.
+
+To improve this, `Proxmox Backup`_ Server uses dynamically sized chunks
+instead. Instead of splitting an image into fixed sizes, it first generates a
+consistent file archive (:ref:`pxar <pxar-format>`) and uses a rolling hash
+over this on-the-fly generated archive to calculate chunk boundaries.
+
+We use a variant of Buzhash which is a cyclic polynomial algorithm.  It works
+by continuously calculating a checksum while iterating over the data, and on
+certain conditions it triggers a hash boundary.
+
+Assuming that most files of the system that is to be backed up have not
+changed, eventually the algorithm triggers the boundary on the same data as a
+previous backup, resulting in chunks that can be reused.
+
+Encrypted Chunks
+^^^^^^^^^^^^^^^^
+
+Encrypted chunks are a special case. Both fixed- and dynamically sized chunks
+can be encrypted, and they are handled in a slightly different manner than
+normal chunks.
+
+The hashes of encrypted chunks are calculated not with the actual (encrypted)
+chunk content, but with the plaintext content concatenated with the encryption
+key. This way, two chunks of the same data encrypted with different keys
+generate two different checksums and no collisions occur for multiple
+encryption keys.
+
+This is done to speed up the client part of the backup, since it only needs to
+encrypt chunks that are actually getting uploaded. Chunks that exist already in
+the previous backup, do not need to be encrypted and uploaded.
+
+Caveats and Limitations
+-----------------------
+
+Notes on hash collisions
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+Every hashing algorithm has a chance to produce collisions, meaning two (or
+more) inputs generate the same checksum. For SHA-256, this chance is
+negligible.  To calculate such a collision, one can use the ideas of the
+'birthday problem' from probability theory. For big numbers, this is actually
+infeasible to calculate with regular computers, but there is a good
+approximation:
+
+.. math::
+
+ p(n, d) = 1 - e^{-n^2/(2d)}
+
+Where `n` is the number of tries, and `d` is the number of possibilities.
+For a concrete example lets assume a large datastore of 1 PiB, and an average
+chunk size of 4 MiB. That means :math:`n = 268435456` tries, and :math:`d =
+2^{256}` possibilities. Inserting those values in the formula from earlier you
+will see that the probability of a collision in that scenario is:
+
+.. math::
+
+ 3.1115 * 10^{-61}
+
+For context, in a lottery game of guessing 6 out of 45, the chance to correctly
+guess all 6 numbers is only :math:`1.2277 * 10^{-7}`, that means the chance of
+collission is about the same as winning 13 such lotto games *in a row*.
+
+In conclusion, it is extremely unlikely that such a collision would occur by
+accident in a normal datastore.
+
+Additionally, SHA-256 is prone to length extension attacks, but since there is
+an upper limit for how big the chunk are, this is not a problem, since a
+potential attacker cannot arbitrarily add content to the data beyond that
+limit.
+
+File-based Backup
+^^^^^^^^^^^^^^^^^
+
+Since dynamically sized chunks (for file-based backups) are created on a custom
+archive format (pxar) and not over the files directly, there is no relation
+between files and the chunks. This means  that the Proxmox Backup client has to
+read all files again for every backup, otherwise it would not be possible to
+generate a consistent independent pxar archive where the original chunks can be
+reused. Note that there will be still only new or change chunks be uploaded.
+
+Verification of encrypted chunks
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+For encrypted chunks, only the checksum of the original (plaintext) data is
+available, making it impossible for the server (without the encryption key), to
+verify its content against it. Instead only the CRC-32 checksum gets checked.

docs/terminology.rst

@@ -1,3 +1,5 @@
+.. _terminology:
+
 Terminology
 ===========
 
@@ -99,6 +101,7 @@ Backup Group
 The tuple ``<type>/<ID>`` is called a backup group. Such a group
 may contain one or more backup snapshots.
 
+.. _backup_snapshot:
 
 Backup Snapshot
 ---------------

src/api2/tape/backup.rs

@@ -131,11 +131,9 @@ fn backup_worker(
     let _lock = MediaPool::lock(status_path, &pool_config.name)?;
 
     task_log!(worker, "update media online status");
-    let has_changer = update_media_online_status(drive)?;
+    let changer_name = update_media_online_status(drive)?;
 
-    let use_offline_media = !has_changer;
-
-    let pool = MediaPool::with_config(status_path, &pool_config, use_offline_media)?;
+    let pool = MediaPool::with_config(status_path, &pool_config, changer_name)?;
 
     let mut pool_writer = PoolWriter::new(pool, drive)?;
 
@@ -168,17 +166,13 @@ fn backup_worker(
 }
 
 // Try to update the the media online status
-fn update_media_online_status(drive: &str) -> Result<bool, Error> {
+fn update_media_online_status(drive: &str) -> Result<Option<String>, Error> {
 
     let (config, _digest) = config::drive::config()?;
 
-    let mut has_changer = false;
-
     if let Ok(Some((mut changer, changer_name))) = media_changer(&config, drive) {
 
-        has_changer = true;
-
-        let label_text_list = changer.online_media_label_texts()?;
+         let label_text_list = changer.online_media_label_texts()?;
 
         let status_path = Path::new(TAPE_STATUS_DIR);
         let mut inventory = Inventory::load(status_path)?;
@@ -189,9 +183,11 @@ fn update_media_online_status(drive: &str) -> Result<bool, Error> {
             &changer_name,
             &label_text_list,
         )?;
-    }
 
-    Ok(has_changer)
+        Ok(Some(changer_name))
+    } else {
+        Ok(None)
+    }
 }
 
 pub fn backup_snapshot(

src/api2/tape/media.rs

@@ -86,8 +86,8 @@ pub async fn list_media(pool: Option<String>) -> Result<Vec<MediaListEntry>, Err
 
         let config: MediaPoolConfig = config.lookup("pool", pool_name)?;
 
-        let use_offline_media = true; // does not matter here
-        let pool = MediaPool::with_config(status_path, &config, use_offline_media)?;
+        let changer_name = None; // does not matter here
+        let pool = MediaPool::with_config(status_path, &config, changer_name)?;
 
         let current_time = proxmox::tools::time::epoch_i64();
 

src/api2/tape/restore.rs

@@ -24,6 +24,8 @@ use proxmox::{
 };
 
 use crate::{
+    task_log,
+    task::TaskState,
     tools::compute_file_csum,
     api2::types::{
         DATASTORE_SCHEMA,
@@ -55,7 +57,6 @@ use crate::{
         TapeRead,
         MediaId,
         MediaCatalog,
-        ChunkArchiveDecoder,
         MediaPool,
         Inventory,
         file_formats::{
@@ -65,6 +66,7 @@ use crate::{
             PROXMOX_BACKUP_CONTENT_HEADER_MAGIC_1_0,
             PROXMOX_BACKUP_CHUNK_ARCHIVE_MAGIC_1_0,
             MediaContentHeader,
+            ChunkArchiveDecoder,
         },
         drive::{
             TapeDriver,
@@ -159,20 +161,21 @@ pub fn restore(
                 }
             }
 
-            worker.log(format!("Restore mediaset '{}'", media_set));
+            task_log!(worker, "Restore mediaset '{}'", media_set);
             if let Some(fingerprint) = encryption_key_fingerprint {
-                worker.log(format!("Encryption key fingerprint: {}", fingerprint));
+                task_log!(worker, "Encryption key fingerprint: {}", fingerprint);
             }
-            worker.log(format!("Pool: {}", pool));
-            worker.log(format!("Datastore: {}", store));
-            worker.log(format!("Drive: {}", drive));
-            worker.log(format!(
+            task_log!(worker, "Pool: {}", pool);
+            task_log!(worker, "Datastore: {}", store);
+            task_log!(worker, "Drive: {}", drive);
+            task_log!(
+                worker,
                 "Required media list: {}",
                 media_id_list.iter()
                     .map(|media_id| media_id.label.label_text.as_str())
                     .collect::<Vec<&str>>()
                     .join(";")
-            ));
+            );
 
             for media_id in media_id_list.iter() {
                 request_and_restore_media(
@@ -185,7 +188,7 @@ pub fn restore(
                 )?;
             }
 
-            worker.log(format!("Restore mediaset '{}' done", media_set));
+            task_log!(worker, "Restore mediaset '{}' done", media_set);
             Ok(())
         }
     )?;
@@ -249,7 +252,7 @@ pub fn restore_media(
         let current_file_number = drive.current_file_number()?;
         let reader = match drive.read_next_file()? {
             None => {
-                worker.log(format!("detected EOT after {} files", current_file_number));
+                task_log!(worker, "detected EOT after {} files", current_file_number);
                 break;
             }
             Some(reader) => reader,
@@ -287,7 +290,7 @@ fn restore_archive<'a>(
             let snapshot = reader.read_exact_allocated(header.size as usize)?;
             let snapshot = std::str::from_utf8(&snapshot)
                 .map_err(|_| format_err!("found snapshot archive with non-utf8 characters in name"))?;
-            worker.log(format!("Found snapshot archive: {} {}", current_file_number, snapshot));
+            task_log!(worker, "Found snapshot archive: {} {}", current_file_number, snapshot);
 
             let backup_dir: BackupDir = snapshot.parse()?;
 
@@ -303,16 +306,16 @@ fn restore_archive<'a>(
                 path.push(rel_path);
 
                 if is_new {
-                    worker.log(format!("restore snapshot {}", backup_dir));
+                    task_log!(worker, "restore snapshot {}", backup_dir);
 
-                    match restore_snapshot_archive(reader, &path) {
+                    match restore_snapshot_archive(worker, reader, &path) {
                         Err(err) => {
                             std::fs::remove_dir_all(&path)?;
                             bail!("restore snapshot {} failed - {}", backup_dir, err);
                         }
                         Ok(false) => {
                             std::fs::remove_dir_all(&path)?;
-                            worker.log(format!("skip incomplete snapshot {}", backup_dir));
+                            task_log!(worker, "skip incomplete snapshot {}", backup_dir);
                         }
                         Ok(true) => {
                             catalog.register_snapshot(Uuid::from(header.uuid), current_file_number, snapshot)?;
@@ -331,7 +334,7 @@ fn restore_archive<'a>(
         }
         PROXMOX_BACKUP_CHUNK_ARCHIVE_MAGIC_1_0 => {
 
-            worker.log(format!("Found chunk archive: {}", current_file_number));
+            task_log!(worker, "Found chunk archive: {}", current_file_number);
             let datastore = target.as_ref().map(|t| t.0);
 
             if let Some(chunks) = restore_chunk_archive(worker, reader, datastore, verbose)? {
@@ -339,7 +342,7 @@ fn restore_archive<'a>(
                 for digest in chunks.iter() {
                     catalog.register_chunk(&digest)?;
                 }
-                worker.log(format!("register {} chunks", chunks.len()));
+                task_log!(worker, "register {} chunks", chunks.len());
                 catalog.end_chunk_archive()?;
                 catalog.commit_if_large()?;
             }
@@ -365,6 +368,9 @@ fn restore_chunk_archive<'a>(
 
     let result: Result<_, Error> = proxmox::try_block!({
         while let Some((digest, blob)) = decoder.next_chunk()? {
+
+            worker.check_abort()?;
+
             if let Some(datastore) = datastore {
                 let chunk_exists = datastore.cond_touch_chunk(&digest, false)?;
                 if !chunk_exists {
@@ -374,14 +380,14 @@ fn restore_chunk_archive<'a>(
                         blob.decode(None, Some(&digest))?; // verify digest
                     }
                     if verbose {
-                        worker.log(format!("Insert chunk: {}", proxmox::tools::digest_to_hex(&digest)));
+                        task_log!(worker, "Insert chunk: {}", proxmox::tools::digest_to_hex(&digest));
                     }
                     datastore.insert_chunk(&blob, &digest)?;
                 } else if verbose {
-                    worker.log(format!("Found existing chunk: {}", proxmox::tools::digest_to_hex(&digest)));
+                    task_log!(worker, "Found existing chunk: {}", proxmox::tools::digest_to_hex(&digest));
                 }
             } else if verbose {
-                worker.log(format!("Found chunk: {}", proxmox::tools::digest_to_hex(&digest)));
+                task_log!(worker, "Found chunk: {}", proxmox::tools::digest_to_hex(&digest));
             }
             chunks.push(digest);
         }
@@ -411,12 +417,13 @@ fn restore_chunk_archive<'a>(
 }
 
 fn restore_snapshot_archive<'a>(
+    worker: &WorkerTask,
     reader: Box<dyn 'a + TapeRead>,
     snapshot_path: &Path,
 ) -> Result<bool, Error> {
 
     let mut decoder = pxar::decoder::sync::Decoder::from_std(reader)?;
-    match try_restore_snapshot_archive(&mut decoder, snapshot_path) {
+    match try_restore_snapshot_archive(worker, &mut decoder, snapshot_path) {
         Ok(()) => Ok(true),
         Err(err) => {
             let reader = decoder.input();
@@ -438,6 +445,7 @@ fn restore_snapshot_archive<'a>(
 }
 
 fn try_restore_snapshot_archive<R: pxar::decoder::SeqRead>(
+    worker: &WorkerTask,
     decoder: &mut pxar::decoder::sync::Decoder<R>,
     snapshot_path: &Path,
 ) -> Result<(), Error> {
@@ -460,6 +468,8 @@ fn try_restore_snapshot_archive<R: pxar::decoder::SeqRead>(
     let mut manifest = None;
 
     loop {
+        worker.check_abort()?;
+
         let entry = match decoder.next() {
             None => break,
             Some(entry) => entry?,

src/bin/proxmox-tape.rs

@@ -45,8 +45,8 @@ use proxmox_backup::{
         complete_media_set_uuid,
         file_formats::{
             PROXMOX_BACKUP_CONTENT_HEADER_MAGIC_1_0,
-            PROXMOX_BACKUP_CONTENT_NAME,
             MediaContentHeader,
+            proxmox_tape_magic_to_text,
         },
     },
 };
@@ -565,7 +565,7 @@ fn debug_scan(param: Value) -> Result<(), Error> {
                     Ok(header) => {
                         if header.magic != PROXMOX_BACKUP_CONTENT_HEADER_MAGIC_1_0 {
                             println!("got MediaContentHeader with wrong magic: {:?}", header.magic);
-                        } else if let Some(name) = PROXMOX_BACKUP_CONTENT_NAME.get(&header.content_magic) {
+                        } else if let Some(name) = proxmox_tape_magic_to_text(&header.content_magic) {
                             println!("got content header: {}", name);
                             println!("  uuid:  {}", header.content_uuid());
                             println!("  ctime: {}", strftime_local("%c", header.ctime)?);

src/tape/drive/linux_tape.rs

@@ -40,15 +40,13 @@ use crate::{
         },
         file_formats::{
             PROXMOX_TAPE_BLOCK_SIZE,
+            PROXMOX_BACKUP_MEDIA_SET_LABEL_MAGIC_1_0,
             MediaSetLabel,
             MediaContentHeader,
-            PROXMOX_BACKUP_MEDIA_SET_LABEL_MAGIC_1_0,
-        },
-        helpers::{
             BlockedReader,
             BlockedWriter,
         },
-    }
+    },
 };
 
 fn run_sg_tape_cmd(subcmd: &str, args: &[&str], fd: RawFd) -> Result<String, Error> {

src/tape/drive/virtual_tape.rs

@@ -30,12 +30,12 @@ use crate::{
             MediaSetLabel,
             MediaContentHeader,
             PROXMOX_BACKUP_MEDIA_SET_LABEL_MAGIC_1_0,
+            BlockedReader,
+            BlockedWriter,
         },
         helpers::{
             EmulateTapeReader,
             EmulateTapeWriter,
-            BlockedReader,
-            BlockedWriter,
         },
     },
 };

src/tape/file_formats/blocked_reader.rs

@@ -49,16 +49,21 @@ impl <R: Read> BlockedReader<R> {
         let (_size, found_end_marker) = Self::check_buffer(&buffer, 0)?;
 
         let mut incomplete = false;
+        let mut got_eod = false;
+
         if found_end_marker {
             incomplete = buffer.flags.contains(BlockHeaderFlags::INCOMPLETE);
+            Self::consume_eof_marker(&mut reader)?;
+            got_eod = true;
         }
+
         Ok(Some(Self {
             reader,
             buffer,
             found_end_marker,
             incomplete,
+            got_eod,
             seq_nr: 1,
-            got_eod: false,
             read_error: false,
             read_pos: 0,
         }))
@@ -101,6 +106,14 @@ impl <R: Read> BlockedReader<R> {
         tape_device_read_block(reader, data)
     }
 
+    fn consume_eof_marker(reader: &mut R) -> Result<(), std::io::Error> {
+        let mut tmp_buf = [0u8; 512]; // use a small buffer for testing EOF
+        if tape_device_read_block(reader, &mut tmp_buf)? {
+            proxmox::io_bail!("detected tape block after stream end marker");
+        }
+        Ok(())
+    }
+
     fn read_block(&mut self) -> Result<usize, std::io::Error> {
 
         if !Self::read_block_frame(&mut self.buffer, &mut self.reader)? {
@@ -118,12 +131,8 @@ impl <R: Read> BlockedReader<R> {
         if found_end_marker { // consume EOF mark
             self.found_end_marker = true;
             self.incomplete = self.buffer.flags.contains(BlockHeaderFlags::INCOMPLETE);
-            let mut tmp_buf = [0u8; 512]; // use a small buffer for testing EOF
-            if tape_device_read_block(&mut self.reader, &mut tmp_buf)? {
-                proxmox::io_bail!("detected tape block after stream end marker");
-            } else {
-                self.got_eod = true;
-            }
+            Self::consume_eof_marker(&mut self.reader)?;
+            self.got_eod = true;
         }
 
         self.read_pos = 0;
@@ -198,8 +207,8 @@ mod test {
     use anyhow::Error;
     use crate::tape::{
         TapeWrite,
-        file_formats::PROXMOX_TAPE_BLOCK_SIZE,
-        helpers::{
+        file_formats::{
+            PROXMOX_TAPE_BLOCK_SIZE,
             BlockedReader,
             BlockedWriter,
         },

src/tape/file_formats/mod.rs

@@ -1,4 +1,23 @@
-//! File format definitions for data written to tapes
+//! File format definitions and implementations for data written to
+//! tapes
+
+mod blocked_reader;
+pub use blocked_reader::*;
+
+mod blocked_writer;
+pub use blocked_writer::*;
+
+mod chunk_archive;
+pub use chunk_archive::*;
+
+mod snapshot_archive;
+pub use snapshot_archive::*;
+
+mod multi_volume_writer;
+pub use multi_volume_writer::*;
+
+mod multi_volume_reader;
+pub use multi_volume_reader::*;
 
 use std::collections::HashMap;
 
@@ -33,8 +52,8 @@ pub const PROXMOX_BACKUP_CHUNK_ARCHIVE_ENTRY_MAGIC_1_0: [u8; 8] = [72, 87, 109,
 pub const PROXMOX_BACKUP_SNAPSHOT_ARCHIVE_MAGIC_1_0: [u8; 8] = [9, 182, 2, 31, 125, 232, 114, 133];
 
 lazy_static::lazy_static!{
-    /// Map content Uuid to human readable names.
-    pub static ref PROXMOX_BACKUP_CONTENT_NAME: HashMap<&'static [u8;8], &'static str> = {
+    // Map content magic numbers to human readable names.
+    static ref PROXMOX_TAPE_CONTENT_NAME: HashMap<&'static [u8;8], &'static str> = {
         let mut map = HashMap::new();
         map.insert(&PROXMOX_BACKUP_MEDIA_LABEL_MAGIC_1_0, "Proxmox Backup Tape Label v1.0");
         map.insert(&PROXMOX_BACKUP_MEDIA_SET_LABEL_MAGIC_1_0, "Proxmox Backup MediaSet Label v1.0");
@@ -44,6 +63,11 @@ lazy_static::lazy_static!{
     };
 }
 
+/// Map content magic numbers to human readable names.
+pub fn proxmox_tape_magic_to_text(magic: &[u8; 8]) -> Option<String> {
+    PROXMOX_TAPE_CONTENT_NAME.get(magic).map(|s| String::from(*s))
+}
+
 /// Tape Block Header with data payload
 ///
 /// All tape files are written as sequence of blocks.

src/tape/file_formats/multi_volume_reader.rs

@@ -0,0 +1,102 @@
+use std::io::{Read};
+
+use anyhow::{bail, Error};
+
+use proxmox::tools::io::ReadExt;
+
+use crate::tape::{
+    TapeRead,
+    file_formats::MediaContentHeader,
+};
+
+/// Read multi volume data streams written by `MultiVolumeWriter`
+///
+/// Note: We do not use this feature currently.
+pub struct MultiVolumeReader<'a> {
+    reader: Option<Box<dyn TapeRead + 'a>>,
+    next_reader_fn: Box<dyn 'a + FnMut() -> Result<Box<dyn TapeRead +'a>, Error>>,
+    complete: bool,
+    header: MediaContentHeader,
+}
+
+impl <'a> MultiVolumeReader<'a> {
+
+    /// Creates a new instance
+    pub fn new(
+        reader: Box<dyn TapeRead +'a>,
+        header: MediaContentHeader,
+        next_reader_fn: Box<dyn 'a + FnMut() -> Result<Box<dyn TapeRead +'a>, Error>>,
+    ) -> Result<Self, Error> {
+
+        if header.part_number != 0 {
+            bail!("MultiVolumeReader::new - got wrong header part_number ({} != 0)",
+                  header.part_number);
+        }
+
+        Ok(Self {
+            reader: Some(reader),
+            next_reader_fn,
+            complete: false,
+            header,
+        })
+    }
+}
+
+impl <'a> Read for MultiVolumeReader<'a> {
+
+    fn read(&mut self, buf: &mut [u8]) -> Result<usize, std::io::Error> {
+        if self.complete {
+            return Ok(0);
+        }
+
+        if self.reader.is_none() {
+            let mut reader = (self.next_reader_fn)()
+                .map_err(|err| proxmox::io_format_err!("multi-volume next failed: {}", err))?;
+
+            proxmox::try_block!({
+                let part_header: MediaContentHeader = unsafe { reader.read_le_value()? };
+                self.reader = Some(reader);
+
+                if part_header.uuid != self.header.uuid {
+                    proxmox::io_bail!("got wrong part uuid");
+                }
+                if part_header.content_magic!= self.header.content_magic {
+                    proxmox::io_bail!("got wrong part content magic");
+                }
+
+                let expect_part_number = self.header.part_number + 1;
+
+                if part_header.part_number != expect_part_number {
+                    proxmox::io_bail!("got wrong part number ({} != {})",
+                                      part_header.part_number, expect_part_number);
+                }
+
+                self.header.part_number = expect_part_number;
+
+                Ok(())
+            }).map_err(|err| {
+                proxmox::io_format_err!("multi-volume read content header failed: {}", err)
+            })?;
+         }
+
+        match self.reader {
+            None => unreachable!(),
+            Some(ref mut reader) => {
+                match reader.read(buf) {
+                    Ok(0) => {
+                        if reader.is_incomplete()? {
+                            self.reader = None;
+                            self.read(buf)
+                        } else {
+                            self.reader = None;
+                            self.complete = true;
+                            Ok(0)
+                        }
+                    }
+                    Ok(n) => Ok(n),
+                    Err(err) => Err(err)
+                }
+            }
+        }
+    }
+}

src/tape/file_formats/multi_volume_writer.rs

@@ -0,0 +1,136 @@
+use anyhow::Error;
+
+use proxmox::tools::Uuid;
+
+use crate::tape::{
+    TapeWrite,
+    file_formats::MediaContentHeader,
+};
+
+/// Writes data streams using multiple volumes
+///
+/// Note: We do not use this feature currently.
+pub struct MultiVolumeWriter<'a> {
+    writer: Option<Box<dyn TapeWrite + 'a>>,
+    next_writer_fn: Box<dyn 'a + FnMut() -> Result<Box<dyn TapeWrite +'a>, Error>>,
+    got_leom: bool,
+    finished: bool,
+    wrote_header: bool,
+    header: MediaContentHeader,
+    header_data: Vec<u8>,
+    bytes_written: usize, // does not include bytes from current writer
+}
+
+impl <'a> MultiVolumeWriter<'a> {
+
+    /// Creates a new instance
+    pub fn new(
+        writer: Box<dyn TapeWrite +'a>,
+        content_magic: [u8; 8],
+        header_data: Vec<u8>,
+        next_writer_fn: Box<dyn 'a + FnMut() -> Result<Box<dyn TapeWrite + 'a>, Error>>,
+    ) -> Self {
+
+        let header = MediaContentHeader::new(content_magic, header_data.len() as u32);
+
+        Self {
+            writer: Some(writer),
+            next_writer_fn,
+            got_leom: false,
+            finished: false,
+            header,
+            header_data,
+            wrote_header: false,
+            bytes_written: 0,
+        }
+    }
+
+    /// Returns the cuntent Uuid with the current part number
+    pub fn uuid_and_part_number(&self) -> (Uuid, usize) {
+        (self.header.uuid.into(), self.header.part_number as usize)
+    }
+}
+
+impl <'a> TapeWrite for MultiVolumeWriter<'a> {
+
+    fn write_all(&mut self, buf: &[u8]) -> Result<bool, std::io::Error> {
+
+        if self.finished {
+            proxmox::io_bail!("multi-volume writer already finished: internal error");
+        }
+
+        if self.got_leom {
+            if !self.wrote_header {
+                proxmox::io_bail!("multi-volume writer: got LEOM before writing anything - internal error");
+            }
+            let mut writer = match self.writer.take() {
+                Some(writer) => writer,
+                None =>  proxmox::io_bail!("multi-volume writer: no writer  -internal error"),
+            };
+            self.bytes_written = writer.bytes_written();
+            writer.finish(true)?;
+        }
+
+        if self.writer.is_none() {
+            if self.header.part_number >= 255 {
+                proxmox::io_bail!("multi-volume writer: too many parts");
+            }
+            self.writer = Some(
+                (self.next_writer_fn)()
+                    .map_err(|err| proxmox::io_format_err!("multi-volume get next volume failed: {}", err))?
+            );
+            self.got_leom = false;
+            self.wrote_header = false;
+            self.header.part_number += 1;
+        }
+
+        let leom = match self.writer {
+            None => unreachable!(),
+            Some(ref mut writer) => {
+                if !self.wrote_header {
+                    writer.write_header(&self.header, &self.header_data)?;
+                    self.wrote_header = true;
+                }
+                writer.write_all(buf)?
+            }
+        };
+
+        if leom { self.got_leom = true; }
+
+        Ok(false)
+    }
+
+    fn bytes_written(&self) -> usize {
+        let mut bytes_written = self.bytes_written;
+        if let Some(ref writer) = self.writer {
+            bytes_written += writer.bytes_written();
+        }
+        bytes_written
+    }
+
+    fn finish(&mut self, incomplete: bool) -> Result<bool, std::io::Error> {
+        if incomplete {
+            proxmox::io_bail!(
+                "incomplete flag makes no sense for multi-volume stream: internal error");
+        }
+
+        match self.writer.take() {
+            None if self.finished => proxmox::io_bail!(
+                "multi-volume writer already finished: internal error"),
+            None => Ok(false),
+            Some(ref mut writer) => {
+                self.finished = true;
+                if !self.wrote_header {
+                    writer.write_header(&self.header, &self.header_data)?;
+                    self.wrote_header = true;
+                }
+                writer.finish(false)
+            }
+        }
+    }
+
+    fn logical_end_of_media(&self) -> bool {
+        self.got_leom
+    }
+
+}

src/tape/helpers/mod.rs

@@ -4,11 +4,5 @@ pub use emulate_tape_writer::*;
 mod emulate_tape_reader;
 pub use emulate_tape_reader::*;
 
-mod blocked_reader;
-pub use blocked_reader::*;
-
-mod blocked_writer;
-pub use blocked_writer::*;
-
 mod snapshot_reader;
 pub use snapshot_reader::*;

src/tape/media_pool.rs

@@ -44,7 +44,9 @@ pub struct MediaPool {
 
     media_set_policy: MediaSetPolicy,
     retention: RetentionPolicy,
-    use_offline_media: bool,
+
+    changer_name: Option<String>,
+
     encrypt_fingerprint: Option<Fingerprint>,
 
     inventory: Inventory,
@@ -55,12 +57,18 @@ pub struct MediaPool {
 impl MediaPool {
 
     /// Creates a new instance
+    ///
+    /// If you specify a `changer_name`, only media accessible via
+    /// that changer is considered available.  If you pass `None` for
+    /// `changer`, all offline media is considered available (backups
+    /// to standalone drives may not use media from inside a tape
+    /// library).
     pub fn new(
         name: &str,
         state_path: &Path,
         media_set_policy: MediaSetPolicy,
         retention: RetentionPolicy,
-        use_offline_media: bool,
+        changer_name: Option<String>,
         encrypt_fingerprint: Option<Fingerprint>,
      ) -> Result<Self, Error> {
 
@@ -75,7 +83,7 @@ impl MediaPool {
             name: String::from(name),
             media_set_policy,
             retention,
-            use_offline_media,
+            changer_name,
             inventory,
             current_media_set,
             encrypt_fingerprint,
@@ -86,7 +94,7 @@ impl MediaPool {
     pub fn with_config(
         state_path: &Path,
         config: &MediaPoolConfig,
-        use_offline_media: bool,
+        changer_name: Option<String>,
     ) -> Result<Self, Error> {
 
         let allocation = config.allocation.clone().unwrap_or_else(|| String::from("continue")).parse()?;
@@ -103,7 +111,7 @@ impl MediaPool {
             state_path,
             allocation,
             retention,
-            use_offline_media,
+            changer_name,
             encrypt_fingerprint,
         )
     }
@@ -272,8 +280,18 @@ impl MediaPool {
     // check if a location is considered on site
     pub fn location_is_available(&self, location: &MediaLocation) -> bool {
         match location {
-            MediaLocation::Online(_) => true,
-            MediaLocation::Offline => self.use_offline_media,
+            MediaLocation::Online(name) => {
+                if let Some(ref changer_name) = self.changer_name {
+                    name == changer_name
+                } else {
+                    // a standalone drive cannot use media currently inside a library
+                    false
+                }
+            }
+            MediaLocation::Offline => {
+                // consider available for standalone drives
+                self.changer_name.is_none()
+            }
             MediaLocation::Vault(_) => false,
         }
     }
@@ -467,16 +485,11 @@ impl MediaPool {
             match media.status() {
                 MediaStatus::Full => { /* OK */ },
                 MediaStatus::Writable if (seq + 1) == media_count =>  {
-                    match media.location() {
-                        MediaLocation::Online(_) => {
-                            last_is_writable = true;
-                        },
-                        MediaLocation::Offline => {
-                            if self.use_offline_media {
-                                last_is_writable = true;
-                            }
-                        }
-                        MediaLocation::Vault(vault) => {
+                    let media_location = media.location();
+                    if self.location_is_available(media_location) {
+                        last_is_writable = true;
+                    } else {
+                        if let MediaLocation::Vault(vault) = media_location {
                             bail!("writable media offsite in vault '{}'", vault);
                         }
                     }

src/tape/mod.rs

@@ -40,12 +40,6 @@ pub use media_pool::*;
 mod media_catalog;
 pub use media_catalog::*;
 
-mod chunk_archive;
-pub use chunk_archive::*;
-
-mod snapshot_archive;
-pub use snapshot_archive::*;
-
 mod pool_writer;
 pub use pool_writer::*;
 

src/tape/pool_writer.rs

@@ -16,15 +16,17 @@ use crate::{
         MAX_CHUNK_ARCHIVE_SIZE,
         COMMIT_BLOCK_SIZE,
         TapeWrite,
-        ChunkArchiveWriter,
         SnapshotReader,
         SnapshotChunkIterator,
         MediaPool,
         MediaId,
         MediaCatalog,
         MediaSetCatalog,
-        tape_write_snapshot_archive,
-        file_formats::MediaSetLabel,
+        file_formats::{
+            MediaSetLabel,
+            ChunkArchiveWriter,
+            tape_write_snapshot_archive,
+        },
         drive::{
             TapeDriver,
             request_and_load_media,

src/tape/test/current_set_usable.rs

@@ -49,7 +49,7 @@ fn test_current_set_usable_1() -> Result<(), Error> {
         &testdir,
         MediaSetPolicy::AlwaysCreate,
         RetentionPolicy::KeepForever,
-        true,
+        None,
         None,
     )?;
 
@@ -75,7 +75,7 @@ fn test_current_set_usable_2() -> Result<(), Error> {
         &testdir,
         MediaSetPolicy::AlwaysCreate,
         RetentionPolicy::KeepForever,
-        true,
+        None,
         None,
     )?;
 
@@ -103,7 +103,7 @@ fn test_current_set_usable_3() -> Result<(), Error> {
         &testdir,
         MediaSetPolicy::AlwaysCreate,
         RetentionPolicy::KeepForever,
-        false,
+        Some(String::from("changer1")),
         None,
     )?;
 
@@ -131,7 +131,7 @@ fn test_current_set_usable_4() -> Result<(), Error> {
         &testdir,
         MediaSetPolicy::AlwaysCreate,
         RetentionPolicy::KeepForever,
-        true,
+        None,
         None,
     )?;
 
@@ -161,7 +161,7 @@ fn test_current_set_usable_5() -> Result<(), Error> {
         &testdir,
         MediaSetPolicy::AlwaysCreate,
         RetentionPolicy::KeepForever,
-        true,
+        None,
         None,
     )?;
 
@@ -189,7 +189,7 @@ fn test_current_set_usable_6() -> Result<(), Error> {
         &testdir,
         MediaSetPolicy::AlwaysCreate,
         RetentionPolicy::KeepForever,
-        true,
+        None,
         None,
     )?;
 
@@ -223,7 +223,7 @@ fn test_current_set_usable_7() -> Result<(), Error> {
         &testdir,
         MediaSetPolicy::AlwaysCreate,
         RetentionPolicy::KeepForever,
-        true,
+        None,
         None,
     )?;
 

src/tools/http.rs

@@ -124,6 +124,11 @@ impl hyper::service::Service<Uri> for HttpsConnector {
                 .ok_or_else(|| format_err!("missing URL scheme"))?
                 == "https";
 
+            let host = dst
+                .host()
+                .ok_or_else(|| format_err!("missing hostname in destination url?"))?
+                .to_string();
+
             let config = this.ssl_connector.configure();
             let dst_str = dst.to_string(); // for error messages
             let conn = this
@@ -135,7 +140,7 @@ impl hyper::service::Service<Uri> for HttpsConnector {
             let _ = set_tcp_keepalive(conn.as_raw_fd(), PROXMOX_BACKUP_TCP_KEEPALIVE_TIME);
 
             if is_https {
-                let conn: tokio_openssl::SslStream<tokio::net::TcpStream> = tokio_openssl::SslStream::new(config?.into_ssl(&dst_str)?, conn)?;
+                let conn: tokio_openssl::SslStream<tokio::net::TcpStream> = tokio_openssl::SslStream::new(config?.into_ssl(&host)?, conn)?;
                 let mut conn = Box::pin(conn);
                 conn.as_mut().connect().await?;
                 Ok(MaybeTlsStream::Right(conn))

www/Dashboard.js

@@ -159,7 +159,7 @@ Ext.define('PBS.Dashboard', {
 		    type = 'sync';
 		}
 
-		if (type.startsWith('verify')) {
+		if (type.startsWith('verif')) {
 		    type = 'verify';
 		}