From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Linton Subject: Re: [PATCH] st: implement sysfs based tape statistics v2 Date: Fri, 6 Feb 2015 11:49:52 -0600 Message-ID: <54D4FEC0.8090101@tributary.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit Return-path: Received: from relay05.mycloudmailbox.com ([199.244.76.202]:39381 "EHLO relay05.mycloudmailbox.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752189AbbBFR6U (ORCPT ); Fri, 6 Feb 2015 12:58:20 -0500 In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: "Seymour, Shane M" , "linux-scsi@vger.kernel.org" Cc: "Kai.Makisara@kolumbus.fi" , "James E.J. Bottomley (JBottomley@parallels.com)" , "jeffm@suse.com" On 1/26/2015 6:11 PM, Seymour, Shane M wrote: > I was wondering if anyone had any feedback or had any chance to review the changes? Per the other discussion about having the same stat format forever. It seems to me that you might want to preemptively add a few additional counters. A counter for WRITE_FILEMARKS, particularly non immediate count=0 ones, which are often used to flush the drive write buffer. A counter for movement related commands like SPACE/LOCATE/REWIND would also be helpful. Finally, abnormal read conditions like, ILI's, and hit FMs should have their own stat. Those three should provide a better view into how the drive is being used and why performance may not be what is expected. There may be others, but those three are high on my list of things I want to know about a tape stream that is not performing up to expectations.