From debbugs-submit-bounces@debbugs.gnu.org Sat Dec 25 17:23:24 2021 Received: (at 51787) by debbugs.gnu.org; 25 Dec 2021 22:23:24 +0000 Received: from localhost ([127.0.0.1]:40001 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1n1FRj-0008Bc-Px for submit@debbugs.gnu.org; Sat, 25 Dec 2021 17:23:24 -0500 Received: from sender4-of-o52.zoho.com ([136.143.188.52]:21282) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1n1FRf-0008BQ-1o for 51787@debbugs.gnu.org; Sat, 25 Dec 2021 17:23:22 -0500 ARC-Seal: i=1; a=rsa-sha256; t=1640470993; cv=none; d=zohomail.com; s=zohoarc; b=DT/OMetXxde1isvecV4fU0rPqKKa8PGLsESvTYC9p2uNHSSshHlBrUI4B0QqwO2gumLSI91S0DhJa/PCQm+KpKAB54VdexcT+3k8M2sZWn4cEOaQ39nduOQ6RcDguzVzTsbwXGZubjoXbmLhW4OBTheF3BE7bPoXpQbYNzm1cy8= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1640470993; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:MIME-Version:Message-ID:References:Subject:To; bh=VY+1RNnbRdxSzBwvgxcH39KfMkZE/8/MXaRN2E99tno=; b=PcgyoR8S2hrNYNLonDRGzJRpbPc0vOH6QkDQBGYkEyj+Ap5dX401xxaHrxCbLkHJNCqbSCkCCTQ111mNHzyoDSqLZUxIQV1csbH1RgdqfZOjYeRIB7Z9R7eRYBTwaedDcGKJEM37Ej82ZWTCNaxRQSAEWrnCjrQHkI0vPKOep2s= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=pass header.i=elephly.net; spf=pass smtp.mailfrom=rekado@elephly.net; dmarc=pass header.from= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; t=1640470993; s=zoho; d=elephly.net; i=rekado@elephly.net; h=References:From:To:Cc:Subject:Date:In-reply-to:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding; bh=VY+1RNnbRdxSzBwvgxcH39KfMkZE/8/MXaRN2E99tno=; b=FJJldJl9Jcu0ZRzKjFwYTaZD8p6Y81JveYnmXIsbtI8MWqPh1u8IUDnMlN/CC4QL oRn8/pgHNl7rGQX3572P2Q+MhMrCLsotxpbLc5cDedePRPgecBoqnZSbZgEkUg6UuiH XeykWOSKAWLYum9UwzTNIteuNQ7qcfL7/lpyu6rk= Received: from localhost (p4fd5a901.dip0.t-ipconnect.de [79.213.169.1]) by mx.zohomail.com with SMTPS id 1640470990202742.1489485710027; Sat, 25 Dec 2021 14:23:10 -0800 (PST) References: <875yrjpi1y.fsf@elephly.net> <87o85bjjpm.fsf@gnu.org> <871r27p5jq.fsf@elephly.net> <87a6gv3pue.fsf@gnu.org> <87v8zhn9m1.fsf@elephly.net> User-agent: mu4e 1.6.10; emacs 27.2 From: Ricardo Wurmus To: Mathieu Othacehe Subject: Re: Disk performance on ci.guix.gnu.org Date: Sat, 25 Dec 2021 23:19:23 +0100 In-reply-to: <87v8zhn9m1.fsf@elephly.net> X-URL: https://elephly.net X-PGP-Key: https://elephly.net/rekado.pubkey X-PGP-Fingerprint: BCA6 89B6 3655 3801 C3C6 2150 197A 5888 235F ACAC Message-ID: <87wnjsjpdh.fsf@elephly.net> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-ZohoMailClient: External X-Spam-Score: -0.0 (/) X-Debbugs-Envelope-To: 51787 Cc: 51787@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -1.0 (-) Ricardo Wurmus writes: > Today we discovered a few more things and discussed them on IRC. Here=E2= =80=99s > a summary. > > /var/cache sits on the same storage as /gnu. We mounted the 5TB ext4 > file system that=E2=80=99s hosted by the SAN at /mnt_test and started cop= ying > over /var/cache to /mnt_test/var/cache. Transfer speed was considerably > faster (not *great*, but reasonably fast) than the copy of > /gnu/store/trash to the same target. Turns out that space on the SAN is insufficient for a full copy of /var/cache. We=E2=80=99ve hit ENOSPC after 4.2TB. The SAN enforces some headroom to remain free, so it denies us full access to the 5TB slice. Bummer. I guess we=E2=80=99ll have to wait for the SAN extension some time early 20= 22 before we can relocate the substitutes cache. Should we attempt to overwrite /gnu/store and rely exclusively on substitutes from the cache? No matter how we look at it, the huge store is a performance problem for us. Today I had to kill =E2=80=99guix gc=E2=80=99 after the GC lock had be= en held for about 24 hours. We will keep having this problem. --=20 Ricardo