Radovan, > i am testing AVS replication on two x4500 boxes. everything works > fine except i have problems with speed. it makes no difference if i > set up sync or async replication. AVS kill about 80% of IO power and > syncing is very slow... that means about !5Mb/s on a !Gbps dedicated > interface. i've tried it with opensolaris svn_91 and svn_97. > > so my question is: is there any way to make this run faster? is > there any possibility to tune AVS?
The most common performance problem often overlook with AVS, is the performance of the disks on which AVS is configured. I would believe this is your case, as indicated by your 80% of I/O number above. Although the initial syncing is done in block-order (sequential access), there is one or more corresponding bitmap volumes that need to be maintained too. If all of these bitmaps are on the same volume, or on the same volume as the actual data being replicated, sequential I/O will look become random I/O to the underling disks. In the "perfect" world, replicated data and replication bitmaps would be on separate volumes, eliminating any disk head seeking. What is the performance of the underlying disks across all volumes? iostat will list data for not only the primary volumes being replicated, but the SNDR volumes as kstat instances. dsstat, the AVS specific utility, shows similar data, but real volume names are displayed, and associated volumes will be grouped together. When looking at I/O performance, I often run two windows next to each other, so that I can see both the Solaris and AVS performance cost to replicate. - Jim > > > thaks a lot, > > radovan > _______________________________________________ > storage-discuss mailing list > [email protected] > http://mail.opensolaris.org/mailman/listinfo/storage-discuss Jim Dunham Engineering Manager Storage Platform Software Group Sun Microsystems, Inc. _______________________________________________ storage-discuss mailing list [email protected] http://mail.opensolaris.org/mailman/listinfo/storage-discuss
