From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Martin K. Petersen" Subject: Re: optimal io size / custom alignment Date: Tue, 16 Jun 2015 17:28:20 -0400 Message-ID: References: <20150615133154.GV1992@ws.net.home> Mime-Version: 1.0 Content-Type: text/plain Return-path: Received: from aserp1040.oracle.com ([141.146.126.69]:37177 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752307AbbFPV2a (ORCPT ); Tue, 16 Jun 2015 17:28:30 -0400 In-Reply-To: (Tom Yan's message of "Wed, 17 Jun 2015 03:26:20 +0800") Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Tom Yan Cc: "Martin K. Petersen" , linux-scsi@vger.kernel.org, Karel Zak , util-linux@vger.kernel.org, linux-usb@vger.kernel.org >>>>> "Tom" == Tom Yan writes: Tom> All drives I have are flash drives so none of them reports 4k Tom> physical sectors. There are plenty of SSDs that report 4K physical sectors, fwiw. Tom> The usb-storage driver does not read vpd so it won't be a thing, Tom> but the the uas driver does. We gave up on USB-SATA bridges long ago. Their designers appear to have a pretty comprehensive misunderstanding of both the ATA and SCSI protocols. We had higher hopes for UAS since it provided a clean slate. So far, however, the results are equally discouraging. Tom> I just feel like the kernel shouldn't bind values from totally Tom> different source (raid stripe vs vpd limit) to the same variable. RAID devices communicate the stripe width through the Block Limits VPD. -- Martin K. Petersen Oracle Linux Engineering