On Thursday 08 July 2010 00:06:39 Brem Belguebli wrote: > > > -- > > > dm-devel mailing list > > > dm-devel@xxxxxxxxxx > > > https://www.redhat.com/mailman/listinfo/dm-devel > > > > Maybe adding this one while doing a test with both paths active during > > "off hours", so no other intrusive factors: > > > > Version 1.03e ------Sequential Output------ --Sequential Input- -- > > Random- > > -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- -- > > Seeks-- > > Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP > > /sec %CP > > xen3 8G 66510 93 80841 21 26821 1 45368 58 72095 2 > > 361.2 0 > > ------Sequential Create------ --------Random > > Create-------- > > -Create-- --Read--- -Delete-- -Create-- --Read--- - > > Delete-- > > files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP > > /sec %CP > > 16 5295 98 +++++ +++ +++++ +++ 5318 98 +++++ +++ > > 17089 100 > > xen3,8G,66510,93,80841,21,26821,1,45368,58,72095,2,361.2,0,16,5295,98,+++ > >++, +++,+++++,+++,5318,98,+++++,+++,17089,100 > > > > > > it show that the speed is exactly 70% of the speed when doing tests > > locally. So this might be the iSCSI TCP overhead. > > > > Should the speed of two round robin paths not compensate for this loss? > > Or is my local storage just to slow to have multipath having any benefit > > speed wise? > > To calculate your theoretical TCP throughput, a simple formula can be > applied : TP= TCP Window size / RTT > > In addition to this generally, you can take advantage of path > load-balancing IO's to capable to multiplex IO's devices , such as SAN > arrays with cache frontend. > Trying to load-balance on a single physical device, won't be, IMHO, of > any help except for pure failover purposes. > > > thx! > > > > B. > > > > -- > > dm-devel mailing list > > dm-devel@xxxxxxxxxx > > https://www.redhat.com/mailman/listinfo/dm-devel > > -- > dm-devel mailing list > dm-devel@xxxxxxxxxx > https://www.redhat.com/mailman/listinfo/dm-devel > Hi Brem, are you talking about storage with a sort of built-in active/active storage cluster? Do you think I don't have added speed because if the fact that both iSCSI targets point to the same storage device? thx!! Bart -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
