Re: IDS 10 disk configuration

Neil Truby schrieb: > "Art S. Kagel" <kagel@bloomberg.net> wrote in message > news:42EFD602.60800@bloomberg.net... > >>david@smooth1.co.uk wrote: >> >>>At checkpoint time chunks are assigned round robin to page cleaners for >>>cleaning. >>> >>>ONE CHUNK WILL ONE GET ONE PAGE CLEANERS FLUSHING IT'S >>>WRITES AT CHECKPOINT TIME. >>> >>>We had a 60Gb chunk and someone was loading lots of data into it. >>> >>>5 minute checkpoint interval and checkpoints up to 6 minutes long! >>> >>>Just what I needed when running a program that inserts into temp >>>tables. >>> >>>My program went from 2 minutes to 20 minutes! >> >>Good point David. The solution would be to use fractional values for >>LRU_MIN/MAX_DIRTY to make sure that there are very few dirty pages at >>checkpoint time. Not a complete solution, but it will help with 'larger' >>chunks if not 'huge' ones. > > > > Are you both saying that an inevitable consequence of large chunks is long > checkpoint times at times of high update? > > I guess this isn't just an IDS 10 thing ...? > > smaller cunks are better chunks .... Always worth the trouble (what trouble is it?) you have with administration! Also in partitioning your I/O subsystem: More LUNs are better LUNs, as the drivers create two queues per LUN (one for immediately startable I/O, and one if you are >throttle value) -> more LUNs = better I/O parallelism, when using KAIO. dic_k -- Richard Kofler SOLID STATE EDV Dienstleistungen GmbH Vienna/Austria/Europe