Re: 2Gb vs 4Gb Disks - Which is faster????

flundy@ix.netcom.com(Frank J. Lundy ) wrote: >In <4j9bfq$l8h@atglab10.atglab.bls.com> >melvin.mariney2@bridge.bellsouth.com (Melvin Mariney) writes: >> >> >>We are trying to decide whether to go with 2gb or 4gb HP drives for >>our database using Informix. The HP salesman says that the 4gb drives >>are faster than the 2gb drives which is probably true. What I would >>prefer though is to go with many smaller 2gb drives so that I can >>spread my database tables out across as many separate physical disks >>as possible rather than having to put more tables on a larger disk. My >>logic says that 2 i/o's on two physical disks will normally be faster >>than 2 i/o's going to 1 physical disk especially if I'm on a multi-cpu >>box and am able to do the i/o in parallel. >> >>I would appreciate any comments or experiences regrading using HP 2gb >>vs 4gb in terms of performance. Thanks in advance. >> >>-- >> >>Melvin Mariney, Informix DBA >>e-mail: melvin.mariney2@bridge.bellsouth.com >> > >More spindles == better performance. Be careful w/ the drives though. >Most newer drives are 7200RPM w/ 1024K cache and ~8ms access time. I >do know one thing, HP drives are *VERY* expensive compared to the mkt >at large. Try a third party- you'll probably cut your disk costs in >half. Generally, I agree; more spindles will improve performance, but the greatest single improvement will be obtained by having dedicated spindles for Informix physical/logical logs and temporary dbspaces. These could be 2GB (or smaller) with no problems. The 4GB drives are fast, but given the amount of data they store they are less tolerant of configuration mistakes; for example, putting high activity tables on dbspaces at oppposite extremes of the disk will absolutely cripple performance. Lay your database out carefully, however, and they will perform better than the 2GB drives. YMMV, but if you are running OnLine Dynamic Server with enough memory, you may find your i/os are being satisfied mostly from cache anyway. The comment above applies to any supplier's 4GB drives, irrespective of cost ;-) -- +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ + Tony da Franca, Hewlett Packard UK + + Any views expressed are my own, not Hewlett Packard's + + E-mail: tony_dafranca@hp-unitedkingdom-om7.om.hp.com + +++++++++++++++++++++++++++++++++++++++++++++++++++++++++