From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [212.224.123.68]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id C297E6538E for ; Wed, 22 Jul 2020 15:57:07 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id A2102210BD for ; Wed, 22 Jul 2020 15:56:37 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [212.186.127.180]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS id 2284B21091 for ; Wed, 22 Jul 2020 15:56:35 +0200 (CEST) Received: from proxmox-new.maurer-it.com (localhost.localdomain [127.0.0.1]) by proxmox-new.maurer-it.com (Proxmox) with ESMTP id DC9DC43325 for ; Wed, 22 Jul 2020 15:56:34 +0200 (CEST) From: Stefan Reiter To: pbs-devel@lists.proxmox.com Date: Wed, 22 Jul 2020 15:56:20 +0200 Message-Id: <20200722135625.23653-1-s.reiter@proxmox.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SPAM-LEVEL: Spam detection results: 0 AWL 0.017 Adjusted score from AWL reputation of From: address KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment RCVD_IN_DNSWL_MED -2.3 Sender listed at https://www.dnswl.org/, medium trust SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record URIBL_BLOCKED 0.001 ADMINISTRATOR NOTICE: The query to URIBL was blocked. See http://wiki.apache.org/spamassassin/DnsBlocklists#dnsbl-block for more information. [index.rs, lib.rs, restore.rs] Subject: [pbs-devel] [PATCH v2 0/5] Fix PBS blockdriver for non-VM settings X-BeenThere: pbs-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox Backup Server development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Jul 2020 13:57:07 -0000 When using the PBS blockdriver with qemu-nbd (for example), it can happen that enough read requests are issued to saturate the tokio thread pool. Not an issue in general, but as me and Wolfgang painstakenly discovered a while back, it does break block_on, which is used in BufferedFixedReader. This means that reading larger amounts of data would hang the QEMU process [0]. Fix this by replacing the BufferedFixedReader with an AsyncIndexReader, implementing AsyncSeek for it in the process. This makes the entire API async, requiring no block_on anymore. Incidentally, this also gave me my best benchmark results yet, coming in at above 1.6 Gb/s read speed via NBD on my local machine. Additionally I discovered a seperate bug (fixed by patch 5), wherein read requests that we're not aligned to the chunk size would return bogus data. This too only seems to happen in non-VM connections (e.g. nbd, etc...). v2: * Remove BufferedFixedReader entirely, use AsyncIndexReader instead * Implement AsyncSeek for AsyncIndexReader * Fix the second bug in Rust instead of QEMU C [0] ...and since the NBD kernel driver appears to be horribly broken, this often also crashes most of the system, but that's a different story. If you ever get in this situation, 'nbd-client -d /dev/nbdX' works (sometimes) to force disconnect the device ('qemu-nbd -d' intelligently issues a read before disconnecting, thus hanging before getting anything done...) backup: Stefan Reiter (3): add and implement chunk_from_offset for IndexFile implement AsyncSeek for AsyncIndexReader remove BufferedFixedReader interface src/backup/async_index_reader.rs | 116 ++++++++++++++++++---- src/backup/dynamic_index.rs | 18 ++++ src/backup/fixed_index.rs | 165 +++---------------------------- src/backup/index.rs | 4 + 4 files changed, 129 insertions(+), 174 deletions(-) backup-qemu: Stefan Reiter (2): use AsyncIndexReader for read_image_at read_image_at: iterate until buffer is filled current-api.h | 4 ++-- src/lib.rs | 4 ++-- src/restore.rs | 35 +++++++++++++++++++++++------------ 3 files changed, 27 insertions(+), 16 deletions(-) -- 2.20.1