From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lb0-f172.google.com ([209.85.217.172]:33608 "EHLO mail-lb0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751332AbbDLKv1 (ORCPT ); Sun, 12 Apr 2015 06:51:27 -0400 Received: by lbbzk7 with SMTP id zk7so40425168lbb.0 for ; Sun, 12 Apr 2015 03:51:24 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: Date: Sun, 12 Apr 2015 11:51:24 +0100 Message-ID: Subject: Re: during fio scenario with verify=meta some jobs fails From: Sitsofe Wheeler Content-Type: text/plain; charset=UTF-8 Sender: fio-owner@vger.kernel.org List-Id: fio@vger.kernel.org To: Samuel Shapiro Cc: "fio@vger.kernel.org" On 12 April 2015 at 11:12, Samuel Shapiro wrote: > Thanks for the great answer Sitsofe :) > Will stick to md5 verification while testing FS data integrity. If fio is in any shape or form CPU bound during writing or verification I'd probably hint to you that crc32c-intel might be better tradeoff if fio is running on recent Intel hardware. If you can't use that (because you aren't on that hardware) you could use xxhash instead. Both crc32c-intel and xxhash will "detect" less corruptions than md5 (their checksum is smaller) but they can be dramatically faster and perhaps allow you to get more runs / more concurrency in and will still detect common problems. I failed to answer question 3. of your original mail: > 3. How can I parse ".state" file so I could compare its data to > original file on storage? You only need to use this file if the writing pass is interrupted before it could be fully completed (so you know when to stop verifying). I don't think it records the contents of the data being written but rather how starting parameters and how far along a given data generation sequence you got (so you have enough to replay it later)... Generally speaking and assuming the verification header part of a block isn't corrupt, verify_dump can be used to make fio dump the expected and mismatched data into two files for later inspection when a mismatch is found. If memory serves, non important parts of the header section may not match between the expected and actual dumps (e.g. padding between the real values might not match up). -- Sitsofe | http://sucs.org/~sits/