From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lan Subject: Multipath Statistics Date: Wed, 13 Apr 2005 10:41:49 -0700 Message-ID: Reply-To: tranlan@us.ibm.com, device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids Hi all, Thought it would be a good time to bring up a discussion on the type of statistics that dm-multipath would find useful, e.g. for a load balancing path selection algorithm or for users. This is a list of statistics provided by an IBM multipathing product. (The discussion of how to gather these type of statistics would also require another discussion). Any thoughts/suggestions? Per Path Information: =20 - Number of times the path was selected for I/O - Number of I/O errors on this path =09 Per Adapter Information : - The number of times this adapter was selected for I/O - The number of errors on all paths attached to this adapter - The number of paths attached to this adapter - The number of functional paths attached to this adapter (i.e. Exclude failed or offline paths) =20 Path Performance Information (more specific breakdown): =09 Total Read I/O: Total number of completed read requests Total Read Sector: Total number of sectors that have been read Total Write I/O: Total number of completed write requests Total Write Sector: Total number of sectors that have been written Active Read I/O: Total number of read requests in process Active Read Sector: Total number of sectors to read in process Active Write I/O: Total number of write requests in process Active Write Sector: Total number of sectors to write in process Maximum I/O: The maximum number of active I/O requests Maximum Sector: The maximum number of active sectors to read or write Transfer Size:=09 <=3D X , (X =3D {512, 4K, 16K, 64K}) The number of I/O requests received whose transfer size is X bytes or less > 64K The number of I/O requests received whose transfer size is greater= than 64KB =09 Adapter Performance Information: ** identical to Path performance information except no "Transfer Size'" i= nfo Thanks! Lan