Re: SCSI vs SATA

[Geoff Tolley <geoff@xxxxxxxxxxxxxx>]

david@xxxxxxx wrote:

> for that matter, with 20ish 320G drives, how large would a parition be 
> that only used the outer pysical track of each drive? (almost certinly 
> multiple logical tracks) if you took the time to set this up you could 
> eliminate seeking entirely (at the cost of not useing your capacity, but 
> since you are considering a 12x range in capacity, it's obviously not 
> your primary concern)

Good point: if 8x73GB in a RAID10 is an option, the database can't be 
larger than 292GB, or 1/12 the available space on the 320GB SATA version.

> note that the CMU and Google studies both commented on being surprised 
> at the lack of difference between the reliability of SCSI and SATA drives.

I'd read about the Google study's conclusions on the failure rate over time 
of drives; I hadn't gotten wind before of it comparing SCSI to SATA drives. 
I do wonder what their access patterns are like, and how that pertains to 
failure rates. I'd like to think that with smaller seeks (like in the 
many-big-SATAs-option) the life of the drives would be longer.

Oh, one big advantage of SATA over SCSI: simple cabling and no need for 
termination. Although SAS levels that particular playing field.

Cheers,
Geoff