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) server-digest SHA256) (No client certificate requested) by lists.proxmox.com (Postfix) with ESMTPS id CA5CB8978 for ; Tue, 22 Aug 2023 13:25:52 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id AC988B848 for ; Tue, 22 Aug 2023 13:25:22 +0200 (CEST) Received: from proxmox-new.maurer-it.com (proxmox-new.maurer-it.com [94.136.29.106]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by firstgate.proxmox.com (Proxmox) with ESMTPS for ; Tue, 22 Aug 2023 13:25:22 +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 CBCA7432F0 for ; Tue, 22 Aug 2023 13:25:21 +0200 (CEST) Date: Tue, 22 Aug 2023 13:25:21 +0200 From: Wolfgang Bumiller To: Fiona Ebner Cc: Proxmox VE development discussion , Lukas Wagner Message-ID: References: <20230821134444.620021-1-l.wagner@proxmox.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SPAM-LEVEL: Spam detection results: 0 AWL 0.103 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: Re: [pve-devel] [RFC storage/proxmox{, -perl-rs} 0/7] cache storage plugin status for pvestatd/API status update calls X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 22 Aug 2023 11:25:52 -0000 On Tue, Aug 22, 2023 at 11:17:14AM +0200, Fiona Ebner wrote: > Am 21.08.23 um 15:44 schrieb Lukas Wagner: > > Open questions: > > - not sure what a good expiration time for cached entries is. For > > now I picked 30s, but there was not much thought behind that value. > > > > If operations affecting the values like allocation, resize, etc. would > invalidate the cache, I think we could go for a bit more. But if they > don't, the limit can't be too high IMHO. Otherwise, users will wonder > why the usage on the storage doesn't change after their action. > > And would it make sense to have the cache be opt-in? So that only > pvestatd would use it, but standalone API/CLI calls always get current > values? If there is invalidation like mentioned above, that might not be > needed, but otherwise, I'm a bit afraid that handing out (slightly) > outdated values might trip up some automated scripts doing batch work or > something. CLI tools should definitely have an explicit cache-opt-out switch (or - for some of them - that might even be a sensible default, but ideally you'd also have a way to quickly check for temporary discrepancies between the cache and the current value via the CLI). But I the API should stick to to using the cache by default. (But can of course also have an explicit cache-opt-out or force-cache-refresh option - whichever makes more sense.) That's kind of the whole idea, to not have 5 daemons query the exact same data simultaneously ;-)