SQL Server Performance Forum – Threads Archive

36GB vs 72GB Performance

I’m under the impression that 72GB drives will outperform 36GB drives when storing the same amount of information. I think this for two reasons: 1) Moving from the outside of the disk in, a larger drive will stay closer to the edge longer – thus limiting head movements and decreasing latency.
2) Because more data will stay closer to the edge, and the edge of the disk turn underneath the disk head at a faster rate (more disk passes per revolution) overall disk transfer rates in MB/s will generally be greater. This is basically correct, right?

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the edge is not relevent, if the data is packed closer together, inside, middle or out, there will be less seek time for otherwise random access to get the most benefit from this, use SCSI/FC or SAS drives, not SATA. (recent SATA drives and controllers supposedly implements NCQ, but i have not seen it work correctly yet) and plan on using 10-20% of the capacity of the disk drive, ie 3.6-7.2GB on a 36GB anf 7.3 to 14.6 on 73GB drive

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Thanks Joe. Yes, they will be SAS drives. RH

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