From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH 1/1] scsi: add Synology to 1024 sector blacklist Date: Tue, 12 Jan 2016 18:54:55 +0100 Message-ID: <56953DEF.1050306@redhat.com> References: <1452206045-18332-1-git-send-email-mchristi@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Return-path: Received: from mail-wm0-f65.google.com ([74.125.82.65]:34642 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752802AbcALRzA (ORCPT ); Tue, 12 Jan 2016 12:55:00 -0500 Received: by mail-wm0-f65.google.com with SMTP id b14so32676083wmb.1 for ; Tue, 12 Jan 2016 09:54:59 -0800 (PST) In-Reply-To: <1452206045-18332-1-git-send-email-mchristi@redhat.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: mchristi@redhat.com, linux-scsi@vger.kernel.org On 07/01/2016 23:34, mchristi@redhat.com wrote: > From: Mike Christie > > Another iscsi target that cannot handle large IOs, > but does not tell us a limit. > > The Synology iSCSI targets report: > > Block limits VPD page (SBC): > Write same no zero (WSNZ): 0 > Maximum compare and write length: 0 blocks > Optimal transfer length granularity: 0 blocks > Maximum transfer length: 0 blocks > Optimal transfer length: 0 blocks > Maximum prefetch length: 0 blocks > Maximum unmap LBA count: 0 > Maximum unmap block descriptor count: 0 > Optimal unmap granularity: 0 > Unmap granularity alignment valid: 0 > Unmap granularity alignment: 0 > Maximum write same length: 0x0 blocks > > and the size of the command it can handle seems to depend on how much > memory it can allocate at the time. This results in IO errors when > handling large IOs. This patch just has us use the old 1024 default > sectors for this target by adding it to the scsi blacklist. We do > not have good contacs with this vendors, so I have not been able to > try and fix on their side. Synology is just (an old fork of?) LIO. IIRC I saw similar problems a couple years ago with LIO because iscsit_map_iovec maps everything a page at a time and produced too large an iovec for the underlying storage. I'm afraid you're going to get this for pretty much every user of LIO. Paolo