Andreas Micklei wrote: > Am Donnerstag, 10. Mai 2007 schrieb Feizhou: >>> Probably not, but is SATA really much worse then SCSI or SAS? I did >>> some testing on a dell PE 2950 of 750GB SATA's vs SAS and SCSI drives, >>> and the SATA drives seem to be faster at least at first glance. I don't >>> have good numbers from the SCSI tests, but at least for sequantial, I'm >>> getting a better speed off the SATAs. >> sequential will be better than SCSI due to the packing on those platters >> which make up for the lack in rpm. NCQ should even up the random ability >> of SATA disks versus SCSI drives but that support has only become >> available lately on Linux and you also need the right hardware (besides >> the right disks). > > SAS and SCSI really has it's place when you need random access with lots of > IOs per second, i.e. Fileserver, Database Server. We upgraded our Fileserver > (NFS, Samba) from SATA SW Raid to SCSI HW Raid and the difference is HUGE. > One the old system a single user doing a large file copy could bring the > system almost to a halt. On the new system you do not even notice if one user > does a similar operation. However plugging one of the same SCSI discs into > your average PC will not give you much advantage. > > There is also a line of SATA discs that aim for the low-end server market, the > WD-Raptors. They spin at 10.000 rpm and give much better random access > performance than normal SATA drives. The price point is very attractive > compared to SCSI and SAS. Great alternative for a tight budget. > > Here is my favorite site for comparing drives. Has nice background articles > too: > http://www.storagereview.com/ I've always wanted a dollars to dollars comparison instead of comparing single components, and I've always thought that a bunch of RAM could make up for slow disks in a lot of situations. Has anyone done any sort of tests that would confirm whether a typical user would get better performance from spending that several hundred dollars premium for scsi on additional ram instead? Obviously this will depend to a certain extend on the applications and how much having additional cache can help it, but unless you are continuously writing new data, most things can live in cache - especially for machines that run continuously. -- Les Mikesell lesmikesell at gmail.com