From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan E Brassow Subject: Re: dm-multipath has great throughput but we'd like more! Date: Thu, 18 May 2006 02:25:13 -0500 Message-ID: References: <1147935929.27006.57.camel@baggage> Reply-To: device-mapper development Mime-Version: 1.0 (Apple Message framework v624) Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1147935929.27006.57.camel@baggage> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: rgautier@redhat.com, device-mapper development List-Id: dm-devel.ids The system bus isn't a limiting factor is it? 64-bit PCI-X will get 8.5 GB/s (plenty), but 32-bit PCI 33MHz got 133MB/s. Can your disks sustain that much bandwidth? 10 striped drives might get better than 200MB/s if done right, I suppose. Don't the switches run at 2 Gbits/s? 2 Gbits/s / 10 (throw in 2 bits for protocol) ~= 200MB/s. Could be a bunch of reasons... brassow On May 18, 2006, at 2:05 AM, Bob Gautier wrote: > Yesterday my client was testing of multipath load balancing and > failover > on a system running ext3 on a logical volume which comprises about ten > SAN LUNs all reached using multipath in multibus mode over two QL2340 > HBAs. > > On the one hand, the client is very impressed: running bonnie++ > (inspired by Ronan's GFS v VxFS example) we get just over 200Mbyte/s > over the two HBAs, and when we pull a link we get about 120MByte/s. > > The throughput and failover response times are better than the client > has ever seen, but we're wondering why we are not seeing higher > throughput per-HBA -- the QL2340 datasheet says it should manage > 200Mbyte/s and all switches etc. run at 2GBps. > > Any ideas? > > Bob Gautier > +44 7921 700996 > > -- > dm-devel mailing list > dm-devel@redhat.com > https://www.redhat.com/mailman/listinfo/dm-devel >