OK, we cut off this thread now.
Bottom line here is that when it comes to making statements about SATA vs SAS, there are ONLY two statements which are currently absolute: (1) a SATA drive has better GB/$ than a SAS drive (2) a SAS drive has better throughput and IOPs than a SATA drive This is comparing apples to apples (that is, drives in the same generation, available at the same time): ANY OTHER RANKING depends on your prioritization of cost, serviceability (i.e. vendor support), throughput, IOPS, space, power, and redundancy. When we have this discussion, PLEASE, folks, ASK SPECIFICALLY ABOUT YOUR CONFIGURATION - that is, to those asking the initial question, SPECIFY your ranking of the above criteria. Otherwise, to all those on this list, DON'T ANSWER - we constantly devolve into tit-for-tat otherwise. That's it, folks. -Erik On Thu, 2008-10-02 at 13:39 -0500, Tim wrote: > > > On Thu, Oct 2, 2008 at 11:43 AM, Joerg Schilling > <[EMAIL PROTECTED]> wrote: > > > > You seem to missunderstand drive physics. > > With modern drives, seek times are not a dominating factor. It > is the latency > time that is rather important and this is indeed > 1/rotanilnal-speed. > > On the other side you did missunderstand another important > fact in drive > physics: > > The sustained transfer speed of a drive is proportional to the > linear data > density on the medium. > > The third mistake you make is to see that confuse the effects > from the > drive interface type with the effects from different drive > geometry. The only > coincidence here is that the drive geometry is typically > updated more > frequently for SATA drives than it is for SAS drives. This > way, you benefit > from the higher data density of a recent SATA drive and get a > higher sustained > data rate. > > BTW: I am not saying it makes no sense to buy SAS drives but > it makes sense to > look at _all_ important parameters. Power consumption is a > really important > issue here and the reduced MTBF from using more disks is > another one. > > Jörg > > -- > > Please, give me a list of enterprises currently using SATA drives for > their database workloads, vmware workloads... hell any workload > besides email archiving, lightly used cifs shares, or streaming > sequential transfers of large files. I'm glad you can sit there with > a spec sheet and tell me how you think things are going to work. I > can tell you from real-life experience you're not even remotely > correct in your assumptions. > > --Tim > > > > _______________________________________________ > zfs-discuss mailing list > zfs-discuss@opensolaris.org > http://mail.opensolaris.org/mailman/listinfo/zfs-discuss -- Erik Trimble Java System Support Mailstop: usca22-123 Phone: x17195 Santa Clara, CA Timezone: US/Pacific (GMT-0800) _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
