From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dennis Chen Subject: question about ceph and FC SAN LUN data IO path Date: Mon, 13 May 2013 20:24:35 +0800 Message-ID: <5190DB83.9010007@tnsoft.com.cn> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from smtpbg297.qq.com ([184.105.67.100]:54203 "HELO smtpbg297.qq.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1751251Ab3EMMWo (ORCPT ); Mon, 13 May 2013 08:22:44 -0400 Sender: ceph-devel-owner@vger.kernel.org List-ID: To: ceph-devel@vger.kernel.org Cc: Dennis Chen Hi, If I have an OSD attached by a FC SAN device with the connection like this: OSD HBA-->FC Switch-->SAN storage device. Then Map a LUN in the SAN to the OSD as its only disk device to save data. if I have a client also has an HBA and the topology diagram looks like: osd client ------- ------- ------- ------- | HBA | | NIC | <---------------> | NIC | | HBA | ---+--- -------- ------- ------- \ / \ / \ / \ -------------- | FC Switch | -------------- | SAN Suppose the created LUN above for OSD can be accessed by both osd and client though FC I/F, the question is: if I create a rbd block device in osd and map it to client, make a file system and mount it in client side, then create a file in the mounted FS. The read/write operation followed for this file will transfer data though ethernet path or FC path? BRs, Dennis