DAN%Irving@VX1.GBA.NYU.EDU (Daniel B Dobkin) (08/03/88)
Our site in London just informed us that local Field Service advises connecting faster disk devices to the higher-numbered requestors on the HSC's would result in a performance gain: RA60's connected to requestor 2, RA82's connected to requestor 9. After we stopped laughing, we called Colorado. Yes, they said, the high-order requestors DO have priority IF there are queued requests AND all other things are equal: latency and seek time of the disks, etc. Does it really make a difference? Probably not, since you're never likely to have many queued requests and the HSC is going to reorder them according to its optimization algorithms. Besides, there are other, more important considerations: shadow set members, for example, shouldn't BOTH be configured on the same requestor! (And writes to shadow sets are by definition queued.) Bottom line: if it really makes a difference to you, Colorado advises hanging more heavily accessed disks off the higher-priority requestors; even that probably doesn't matter much, since the those disks are most likely the only queued requests anyway..... Daniel B Dobkin Irving Trust Co. New York, NY -------