3.7.1 saCkptSectionCreate() "If the checkpoint was created with the SA_CKPT_WR_ALL_REPLICAS property, the section is created in all of the checkpoint replicas when the invocation returns; otherwise, the section has been created at least in the active checkpoint replica when the invocation returns and will be created asynchronously in the other checkpoint replicas."
It looks like the implementation behaves like the checkpoint was created with SA_CKPT_WR_ALL_REPLICAS, (even if SA_CKPT_WR_ACTIVE_REPLICA or SA_CKPT_WR_ACTIVE_REPLICA_WEAK are specified) for section creates. I've been digging into the code, and it looks like "cpnd_evt_proc_ckpt_sect_create" sends a synchronous message to each replica to create the section regardless of the property. I realize this is spec compliant, but performance could be greatly enhanced for large numbers of sections when using the SA_CKPT_WR_ACTIVE_REPLICA or SA_CKPT_WR_ACTIVE_REPLICA_WEAK property by making this asynchronous. Any chance we can change this behaviour, and make it like saCkptCheckpointWrite? Alex On 01/14/2014 03:16 PM, Alex Jones wrote: > AVM, > > In my 5+1 setup, when I have the standby node open all the > checkpoints and read from them, as well as open the hot-standby > callback, the section creates done on the other active nodes can take > a very long time. (For 40k sections, it can sometimes take over 2 > minutes). > > Once the sections have been created, however, subsequent writes > and overwrites are very fast. (Writing 1k data into 40k sections > takes 10 seconds). > > But, if I don't open the checkpoints on the standby, the section > creates on the active nodes are fast (about 22 seconds for 40k > sections), and the write and overwrite performance is basically > unchanged. > > This suggests that there is some kind of synchronous mechanism > going on between replicas when creating sections. > > Can you explain why I am seeing this performance degradation when > creating sections when a standby replica is opened, but there is no > performance hit for writing and overwriting? > > Thanks! > > Alex > ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ Opensaf-devel mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/opensaf-devel
